▲ 8 r/InfinityMath+1 crossposts

Does infinity exist in reality?

No thing that I've observed in our universe is infinite, however there are traces of infinity in my sight.
Draw a circle and either its radius or circumference lives in the π world.
Or many aspects in nature like flowers, develop themselves in a φ ratio (1+sqrt(5))/2.

Even though no event or anything is "Non-ending"/infinite, underneath many aspects of reality there are patterns which can only be fully described using infinity.

You can't describe irrational numbers to their extent without any notion of infinite/limits/sequences... And many aspects within our World show their true behaviour only with aid of infinity.

>!Sure you can take a world that lives in something like 10¹⁰⁰ and it looks like infinity to us, sometimes we only see the difference after the 10⁶ decimal place, nevertheless the pattern they follow is a pattern that only "infinity" can yield to the truest precision.!<

Do you believe the axiom of infinity, and the continuous to really exist? Even if not in the ordinary sense? haha

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u/Another_Little_Star — 10 days ago
▲ 3 r/InfinityMath+1 crossposts

How Common Fractions Helped Me Understand Why 0.999... = 1

I'd like to share what made it understandable to me that 0.999 repeating = 1.

I had heard the familiar statement:
1/3 = 0.333 repeating

So if 1/3 = 0.333 repeating, then it follows that multiplying 0.333 repeating by 3 should give the same result as multiplying 1/3 by 3.

However, that explanation by itself seems to leave out several points that can make it clearer why this works.

NOTE:
If you do not believe 1/3 = 0.333 repeating, use long division to divide 1 by 3. The same remainder occurs again at each division step in base 10, which produces the repeating 3 structure.

SECTION 1: SAME VALUE, DIFFERENT FRACTION FORMS

It helps to separate the value from the form used to represent it.
-> 1/3 is a fractional representation of a value.
-> 0.333 repeating is also a fractional representation of a value.

Here I will refer to these as two different fraction forms:
-> 1/3 is in common fraction form.
-> 0.333 repeating is in decimal fraction form.

By "decimal fraction form," I mean representing a fractional value using decimal notation, including repeating decimals.

These different forms represent the same value:
1/3 = 0.333 repeating

We can make this relationship especially clear by letting:
X = 1/3 = 0.333 repeating

Therefore:
X = 1/3
X = 0.333 repeating

Now consider:
1/3 * 3 = 3/3 = 1

Since:
X = 1/3

then:
X * 3 = 1

But X also equals 0.333 repeating.

So the same multiplication can be represented as:
1/3 * 3 = 3/3 = 1
0.333 repeating * 3 = 0.999 repeating = 1

The value represented by X has not changed. Only the fraction form used to represent that value has changed.

But perhaps you are not yet convinced that multiplying 0.333 repeating by 3 really produces 0.999 repeating.

So let's examine the repeating-decimal multiplication more directly.

SECTION 2: WHERE THE REPEATING DIGITS COME FROM

In base 10, a single repeating digit follows this relationship for the cases below the endpoint we are interested in:
0.n repeating = n/9

for n = 1 through 8.

More generally, in base B, for the non-endpoint digits being considered here:
0.d repeating in base B = d/(B - 1)

where d ranges from 1 through B - 2.

The case involving the largest digit of the base is the endpoint we are examining here, so rather than assuming its result in advance, let's build up to it.

For base 10:

Same Value in Common Fraction Form and Decimal Fraction Form

1/9 = 0.111 repeating
2/9 = 0.222 repeating
3/9 = 0.333 repeating
4/9 = 0.444 repeating
5/9 = 0.555 repeating
6/9 = 0.666 repeating
7/9 = 0.777 repeating
8/9 = 0.888 repeating

What 9/9 equals in decimal fraction form will be explored shortly.

SECTION 3: TESTING THE MULTIPLICATION PATTERN WITH 1/9

Now start with:
1/9 = 0.111 repeating

and multiply both representations by the same whole numbers.

Multiply by 2
-> Common Fraction: 1/9 * 2 = 2/9
-> Decimal Fraction: 0.111 repeating * 2 = 0.222 repeating
-> Therefore: 2/9 = 0.222 repeating

Multiply by 3
-> Common Fraction: 1/9 * 3 = 3/9
-> Decimal Fraction: 0.111 repeating * 3 = 0.333 repeating
-> Therefore: 3/9 = 0.333 repeating

Multiply by 4
-> Common Fraction: 1/9 * 4 = 4/9
-> Decimal Fraction: 0.111 repeating * 4 = 0.444 repeating
-> Therefore: 4/9 = 0.444 repeating

Multiply by 5
-> Common Fraction: 1/9 * 5 = 5/9
-> Decimal Fraction: 0.111 repeating * 5 = 0.555 repeating
-> Therefore: 5/9 = 0.555 repeating

Multiply by 6
-> Common Fraction: 1/9 * 6 = 6/9
-> Decimal Fraction: 0.111 repeating * 6 = 0.666 repeating
-> Therefore: 6/9 = 0.666 repeating

Multiply by 7
-> Common Fraction: 1/9 * 7 = 7/9
-> Decimal Fraction: 0.111 repeating * 7 = 0.777 repeating
-> Therefore: 7/9 = 0.777 repeating

Multiply by 8
-> Common Fraction: 1/9 * 8 = 8/9
-> Decimal Fraction: 0.111 repeating * 8 = 0.888 repeating
-> Therefore: 8/9 = 0.888 repeating

Finding: The values produced by multiplying 0.111 repeating match the already established common-fraction and decimal-fraction pairings.
2/9 = 0.222 repeating
3/9 = 0.333 repeating
4/9 = 0.444 repeating
5/9 = 0.555 repeating
6/9 = 0.666 repeating
7/9 = 0.777 repeating
8/9 = 0.888 repeating

The multiplication in decimal fraction form is also straightforward.

Each repeating 1 is multiplied by the same whole number:
1 * 2 = 2
1 * 3 = 3
1 * 4 = 4
1 * 5 = 5
1 * 6 = 6
1 * 7 = 7
1 * 8 = 8

There is no carrying from one decimal place to another.

So:
0.111 repeating * 2 = 0.222 repeating
0.111 repeating * 3 = 0.333 repeating
0.111 repeating * 4 = 0.444 repeating
0.111 repeating * 5 = 0.555 repeating
0.111 repeating * 6 = 0.666 repeating
0.111 repeating * 7 = 0.777 repeating
0.111 repeating * 8 = 0.888 repeating

This does not require reaching a final decimal place. Since 1/9 and 0.111 repeating represent the same value, multiplying either representation by the same number must produce the same value. The digit pattern simply shows what that multiplication looks like in decimal fraction form.

This establishes a consistent relationship between the common fraction form and the decimal fraction form.

SECTION 4: CONTINUING THE PATTERN TO 9

Section 3 established the same multiplication pattern from *2 through *8. The final case was:

Multiply by 8
-> Common Fraction: 1/9 * 8 = 8/9
-> Decimal Fraction: 0.111 repeating * 8 = 0.888 repeating
-> Therefore: 8/9 = 0.888 repeating

Now continue the exact same pattern one more step.

Multiply by 9
-> Common Fraction: 1/9 * 9 = 9/9
-> Decimal Fraction: 0.111 repeating * 9 = 0.999 repeating

The decimal fraction multiplication follows the same digit pattern established in Section 3. Each repeating 1 is multiplied by 9:
1 * 9 = 9

There is no carrying from one decimal place to another, so every decimal position becomes a 9:
0.111 repeating * 9 = 0.999 repeating

Now remember that the two starting forms represent the same value:
1/9 = 0.111 repeating

We multiplied both representations by the same number, 9:

-> Common Fraction: 1/9 * 9 = 9/9
-> Decimal Fraction: 0.111 repeating * 9 = 0.999 repeating

The starting value is the same.
The multiplication is the same.
Therefore, the resulting value is the same:
9/9 = 0.999 repeating

But:
9/9 = 1

Therefore:
0.999 repeating = 1

SECTION 5: CHECKING THE SAME RESULT WITH 1/3

We can now return to the familiar 1/3 example.

We already know:
3/9 = 1/3 = 0.333 repeating

First multiply by 2.

Using common fractions:
3/9 * 2 = 6/9

Reducing the fractions:
1/3 * 2 = 2/3

Using decimal fractions:
0.333 repeating * 2 = 0.666 repeating

Placed directly together:
3/9 * 2 = 6/9
1/3 * 2 = 2/3
0.333 repeating * 2 = 0.666 repeating

The computation has not changed.
The values have not changed.
Only the fraction form used to represent those values has changed.

Now multiply by 3.

Using common fractions:
3/9 * 3 = 9/9 = 1

If we reduce 3/9 before performing the multiplication:
1/3 * 3 = 3/3 = 1

Using decimal fractions:
0.333 repeating * 3 = 0.999 repeating

Placed directly together:
3/9 * 3 = 9/9 = 1
1/3 * 3 = 3/3 = 1
0.333 repeating * 3 = 0.999 repeating

Again, each repeating 3 is multiplied by 3:
3 * 3 = 9

There is no carrying from one decimal place to another.

So:
0.333 repeating * 3 = 0.999 repeating

But:
1/3 = 0.333 repeating
1/3 * 3 = 1

Therefore:
0.333 repeating * 3 = 1

while:
0.333 repeating * 3 = 0.999 repeating

Therefore:
0.999 repeating = 1

SECTION 6: FINITE 9s ARE NOT THE SAME THING

None of this says that a finite string of 9s equals 1.

0.9 < 1
0.99 < 1
0.999 < 1
0.9999 < 1

Every finite string of 9s is less than 1.

The statement concerns:
0.999 repeating

where the 9s do not terminate.

0.999 repeating is therefore not any particular member of the finite sequence 0.9, 0.99, 0.999, 0.9999, and so on.

That distinction, along with seeing the same values and computations represented in common fraction form and decimal fraction form, is what finally made 0.999 repeating = 1 understandable to me.

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u/Arlo_Tinkerman — 19 days ago

Video Lectures on Infinity - Ergo YouTube Channel - Presented by Professor Joel David Hamkins - University of Notre Dame &amp; previously Oxford

If you are interested in infinity in terms of the history, the ways some ideas are derived for infinite series, and more, I suggest you watch this recent video series.

https://www.youtube.com/playlist?list=PL1GBzfniaE7xWed_5aVa1wb4OR3aouNPx

Here is the description from the playlist itself:

>Professor Joel David Hamkins guides viewers through the great paradoxes and discoveries about infinity, from Zeno's ancient puzzles to Cantor's revolutionary proof that some infinities are larger than others.

Lectures 1-3 available now. Lectures 4-10 coming soon.

Course: Lectures on Infinity
A lecture series by Professor Joel David Hamkins.

Joel David Hamkins opens this course with an intriguing observation: infinity has bewildered thinkers for millennia, yet we have made genuine progress in understanding it. Beginning with Zeno's ancient paradoxes about motion and the impossibility of traversing infinitely many points, Hamkins shows how these puzzles force us to confront what it means to complete an infinite task. The mathematics of infinite sums provides one resolution, but deeper questions remain about whether infinity can ever be grasped as a completed whole.

The course traces the long debate between two conceptions of infinity. For Aristotle and most mathematicians until the nineteenth century, infinity was merely potential: you could always count one more, but never possess all the numbers at once. Hamkins explores how this view shaped ancient geometry and even Archimedes' calculation of areas, before turning to the revolutionary work of Georg Cantor, who insisted that infinite collections could be treated as completed totalities.

Through vivid thought experiments like Hilbert's Hotel, Hamkins reveals the strange arithmetic of the infinite. A hotel with infinitely many rooms can accommodate infinitely many new guests even when completely full. The natural numbers, the integers, and even the rational numbers all turn out to be the same size of infinity: they are countable. But Cantor's diagonal argument presents a different case: the real numbers cannot be counted. There are genuinely different sizes of infinity.

Along the way, Hamkins examines Galileo's paradox about squares and whole numbers, the impossibility of giants according to scaling laws, and the peculiar behavior of supertasks where infinitely many actions occur in finite time. These explorations illuminate how infinity defies ordinary intuition while remaining mathematically coherent.

The course concludes with one of mathematics' great unsolved mysteries: Cantor's continuum hypothesis, which asks whether any infinity lies between the countable infinity and the continuum. Hamkins explains how this question proved undecidable within standard mathematics, leaving a profound puzzle at the heart of set theory. No prior mathematical background is required, only curiosity about one of humanity's most fascinating ideas.

About Joel David Hamkins

Joel David Hamkins is the John Cardinal O'Hara Professor of Logic at the University of Notre Dame. He previously held positions at the University of Oxford, where he was Professor of Logic and Sir Peter Strawson Fellow at University College, and at the City University of New York Graduate Center. His work spans mathematical logic, set theory, philosophy of mathematics, computability theory, and infinite games. His research addresses the set-theoretic multiverse, potentialism, large cardinals, modal logic, infinite-time Turing machines, and the foundations of mathematics. He has also written on infinite chess, computability, and the philosophy of the infinite.

He is the author of The Book of Infinity, Lectures on the Philosophy of Mathematics, Proof and the Art of Mathematics, and Proof and the Art of Mathematics: Examples and Extensions. He writes on mathematics and philosophy at infinitelymore.xyz.

📚 This playlist contains the complete lecture series in order. Start with the introduction and work through at your own pace.

u/Arlo_Tinkerman — 1 month ago
▲ 2 r/InfinityMath+1 crossposts

Dumb question about Cantor's Diagonal Arguement and Irrational numbers

I was over-caffinated this morning and have been wrapping my head around the clip from Futurama with this problem. When comparing the integers and real number sets, when Cantor takes a diagonal sample of the integers is that identifying an irrational number? Is that why it cannot be expressed as a fraction?

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u/Arlo_Tinkerman — 1 month ago

Why math works and to the level it does... from the beginning...

This post is content I left as a comment to another post. That is here.

--

Math formulas work because we stack observations, compress them into representations, observe how those representations behave, compress again, and use logic so the stack does not fall apart when we leave the original examples.

Start with the simplest case. I have a single rock and put it with another single rock. What shall we call that quantity? We call it 2. Put another rock with that grouping and we call that 3. That is not a mysterious law of the universe. It is a naming of what we already see when discrete things are collected.

The number system we use now is base 10. That means 10 symbols per position, 0 through 9. It is a positional system. Positions go together, and a 1 in the next position stands for a completed collection in the previous position. You count 0 through 9, then roll the ones place back to 0 and put a 1 in the next place. That is 10. Same again: 19 to 20, 29 to 30, 99 to 100. We can use other bases. Base 12 has 12 symbols per position. Roman numerals are a different kind of system, not positional in the same way, and they are much more annoying to do math with.

Subtraction is the inverse of that same addition process. We also learned we do not have to add or subtract one rock at a time. 2 + 2 = 4 instead of 1 + 1 + 1 + 1. 4 - 2 = 2 instead of 4 - 1 - 1.

Multiplication is a compression of addition. 2 * 2 means 2 taken 2 times. 2 * 2 * 2 means take 2 two times, then take that result two times. You only know what those products are because you already know the additions underneath. Multiplication tables are a recording of those already-checked observations. Because the system is positional, you only need a limited table. After that you can work position by position.

Division is inverse multiplication. Same tables, run the other way.

Exponents are a compression of multiplication. Roots are the inverse of that. The pattern is stable: compress in the addition direction first, then derive the reverse method.

From there we look at how specific quantities operate with each other, find patterns, and generalize. Induction is one clean version of that move. If a statement holds for 1, and whenever it holds for n it also holds for n+1, then it holds for every counting number. You do not have to inspect every case. You inspect the rule that takes you from one case to the next.

So far that is genesis. Concrete observations become abstractions. Then we watch how the abstractions operate and stack more abstractions on top. Logic is part of that work. It is a representation of how operations hang together, and it is also the tool that lets a conclusion travel farther than the examples that suggested it.

That last part is why formulas keep working in an analysis, and why we still use them.

A formula is not trusted just because someone saw a pattern a few times. People generalize wrongly all the time. What locks the pattern down is a definition plus steps that cannot fail if the definition stands. After that you do not restack the rocks for every new problem. If the steps follow, the result follows.

That matters once you leave piles of rocks. Analysis in the mathematical sense is the part with limits, rates, and accumulation. You cannot line up infinitely many rocks and watch the process finish. So we define what it means for a process to settle as closely as we want. Then we prove formulas from that definition. The formula works because the definition forces it, not because anybody observed every case.

The same symbol also gets extended on purpose. Multiplication starts as repeated addition of counting numbers. Later we define it so the same operation still behaves well with 0, negatives, fractions, and more. The formula stays in use because the extended structure still does the work we needed from the original compression.

Then you get math that looks like a game with made-up rules. That layer is real, but it is not “anything goes.” We choose starting rules, demand that they not contradict each other, and keep a system when it stays coherent and still fits problems we care about. Some of that math is no longer a direct picture of rocks. It is still constrained. Applied formulas survive for a simple reason: the structure we built still matches the situation we are using it on.

If you want the history of numbers themselves, why they became a thing and how they developed, there are good books. I recently bought The Universal History of Numbers: From Prehistory to the Invention of the Computer. 656 pages, hardback. Used on Amazon for about 8 USD. New it is around 100 USD. For a much shorter casual or kid-level version, The History of Number Systems: Place Value (Mathematics in the Real World) is 32 pages and about 13 USD.

A lot of what I described is also on Wikipedia under:
* Positional number system
* Base 10
* Base 12
* Roman numerals
* Mathematical induction
* Limit (mathematics)

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u/Arlo_Tinkerman — 1 month ago

Decimal expansions are written place by place. The value exists before it is written.

This post is content I left as a comment to another post. That is here.

--

When it comes to infinite expansions, it is useful to be aware of some distinctions. When the division of two values produces an infinite expansion, there is the resulting value itself, and there are representations of that value. The representations of infinite expansions most people are familiar with are in base 10, which is a positional number system. The same value can be represented in other number systems, such as base 2, the binary system computers use, or base 12 or base 60, which were used historically.

In the base 10 positional number system, representations can be produced position by position. That does not mean the value itself is produced position by position. The resulting value exists before its representation has been written. If you measure a length, the length exists before the measurement. The measurement is a representation of the length, not the length itself.

An expansion is sometimes talked about as if the number itself keeps increasing or decreasing as more places are written. That treats the building of the representation as if it were the building of the value. Those are not the same thing.

First the representation side, then the value side.

On the representation side of topic:

The digits written so far make a finite decimal. Adding a place changes that finite decimal. The new finite decimal can be larger than the previous one, smaller than the previous one, or the same if the next digit is 0.

That is already visible with short finite decimals. Is 0.9 the same value as 0.99? No. At the second place you could have written any of these instead:

0.91
0.92
0.93
...

The finite decimals I find most useful here are these:

0.98
0.99
1.00

Q1: Is 0.98 a larger or smaller value than 0.99?
Q2: Is 1.00 a larger or smaller value than 0.99?

A1: 0.98 is smaller.
A2: 1.00 is larger.

0.9 and 0.99 are two different finite decimals. 0.99 is larger than 0.9 only because the second digit happened to be 9. The second place could just as well have been 8, which gives 0.98, or the writing could have been 1.00.

0.9, 0.99, 0.999, and so on are also the finite prefixes of the infinite expansion 0.999.... Within the context of the 0.999 repeating scenario, adding a place does not mean the value grew. It means a different finite decimal of that infinite expansion was named, which adds one more place of precision to the representation of the value.

Each added decimal place adds more information to the representation of the complete value. It does not increase or decrease the complete value itself.

The same distinction applies when the expansion does not terminate because of a remainder. 1/3 produces 0.333... because the division always leaves a remainder after each place. The finite prefixes 0.3, 0.33, 0.333, and so on are different finite decimals. Those prefixes can be compared with one another. They are not stages in which 1/3 itself is still being enlarged.

The same thing occurs when the circumference of a circle is divided by the diameter of that same circle. At each place of the expansion you get another digit. That next digit can make the current finite decimal larger or smaller than the one before it, in the same way 0.99 is larger than 0.9, or 0.98 is smaller than 0.99. The extra place adds precision to the representation.

On the value side of topic:

Pi is the value of a ratio: the circumference of a circle divided by the diameter of that same circle. Pi = C / d. That ratio is structurally complete as soon as C and d are fixed. It does not get built place by place. The representation is written place by place. The value is not.

In the case of pi the two lengths are incommensurable. There is no scaling that makes both C and d whole-number multiples of one common unit. A simpler picture is two quantities that will not share a common denominator. That is why the decimal expansion of pi never terminates and never repeats. The ratio is still a specific completed value. The writing is infinite because the two lengths do not share a common measure, not because the ratio is still unfinished.

Representations are just that. They are not the values themselves. The division of circumference by diameter produces a specific value, regardless of the representation and regardless of which base you write it in. Our writings are limited, so we show a few decimal places and say the expansion continues, or we cut it short. Cutting it short is a truncation. The truncation is an estimate of pi, not the value of pi.

An infinite writing can be produced place by place. The value that writing is about is not produced that way.

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u/Arlo_Tinkerman — 1 month ago
▲ 6 r/InfinityMath+1 crossposts

If infinity isn't a number, why can we still do mathematical operations with it?

I often see things like infinity plus infinity or infinity divided by 2 in mathematics. If infinity isn't technically a number, what exactly are we doing when we perform these operations?

Please explain it to me.

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u/Arlo_Tinkerman — 2 months ago
▲ 13 r/InfinityMath+1 crossposts

What are the philosophical prerequisites for the ZFC axioms?

Hey everyone, ​I want to discuss the philosophical motivations behind each of the ZFC axioms. ​Axioms are mathematically true by definition, but what philosophical worldview actually justifies them? For example, does the Axiom of Infinity require strict Platonism, or is it just about our cognitive ability to imagine such concepts? What about the philosophical reasoning behind the Axiom of Choice or Regularity? ​I'd love to hear your thoughts on the reasoning that grounds these axioms, or get recommendations for philosophers who have deeply explored the "why" behind ZFC.

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u/Arlo_Tinkerman — 2 months ago
▲ 1 r/InfinityMath+1 crossposts

Regarding cardinalities

A celebrated mathematical "factoid" is that there are more real numbers than one can count, this seems to be something that troubles people outside of math, it troubles me aswell.

The question is: is there any "real world" application of the fact |R|>|N| that isn't an impossibility statement?

By "real world" I mean whatever someone smarter than me might mean by that, by "impossibility statement" I mean something to the effect of "there are uncomputable numbers".

If there isn't such an application, I can't believe the status quo interpretation: "no really some infinities are bigger than others" of Cantor's argument is better than simply stating that we shall not understand infinity as finite beings.

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u/Arlo_Tinkerman — 2 months ago
▲ 2 r/100monkeys+2 crossposts

Cantors infinity resolved

A Candidate Boundary-Recursive Interpretation of Cantor's Theorem

I've been exploring an alternative interpretation of Cantor's theorem that keeps the diagonal proof intact but proposes a different interpretation of what it demonstrates. I'd appreciate feedback on where this framework succeeds, where it fails, and whether anything similar already exists in the literature.


Step 1 — Cantor's Definition of Size

Cantor defines two sets to have the same size if there exists a bijection between them.

For finite sets this agrees with counting.

For infinite sets it replaces counting entirely.

For example,

ℕ ↔ Even Numbers

via

f(n)=2n

shows that the natural numbers and the even numbers have the same cardinality.


Step 2 — Cantor's Theorem

Cantor then proves there is no bijection

A ↔ ℘(A)

using diagonalization.

The standard conclusion is

|℘(A)| > |A|

which produces the hierarchy

ℵ₀ → 𝔠 → 2^𝔠 → …


Sigma Observation

The diagonal proof unquestionably constructs an object outside every proposed complete correspondence.

My question is whether the proof necessarily establishes larger infinities, or whether it establishes something weaker and more general:

«Every completed representation of an unbounded generative system admits another valid representational transform.»


Sigma Boundary Theory

Suppose mathematics is studying an unbounded generative system.

The recursive process becomes

Reachable System → Draw Boundary → Treat Boundary as Object → Apply Valid Transform → New Boundary → Repeat

The recursion occurs in the representations—not necessarily in infinity itself.


Boundary Interpretation

Under this interpretation:

  • A power set is not viewed primarily as a "larger infinity."
  • It is viewed as a boundary-lifting transform.
  • Diagonalization demonstrates that no completed representation is terminal.

Instead of reading Cantor's theorem as

«"There exists a larger infinity,"»

the same proof may be read as

«"Every completed representation of an unbounded generative system admits another representational closure."»

The mathematics of diagonalization is unchanged.

Only the interpretation changes.


Candidate Replacement Primitive

Rather than ordering mathematical objects by cardinality,

|A| < |B|

Sigma proposes ordering representations by recursive closure:

Closure₀ → Closure₁ → Closure₂ → …

The hierarchy becomes a hierarchy of boundary closures rather than a hierarchy of infinities.

Infinity itself is treated as a single unbounded phenomenon.

What grows is the sequence of completed representations constructed around it.


Candidate Boundary Escape Theorem

Every reflective completed representation of an unbounded generative system admits another valid representational transform.

Equivalently,

Reachable System → Draw Boundary → Treat Boundary as Object → Apply Valid Transform → New Boundary → Repeat

No completed representation is terminal.

Two systems are Sigma-equivalent if

  1. They generate the same reachable universe.
  2. Every valid transform of one corresponds to a valid transform of the other.
  3. Neither admits a boundary escape that the other does not.

The Question

I'm not claiming this disproves Cantor's theorem.

I'm asking whether this provides a viable alternative interpretation of the theorem.

Specifically:

  • Does diagonalization require the ontology of multiple infinities?
  • Or is it sufficient to interpret it as demonstrating the nonexistence of a terminal representation of an unbounded generative system?

I'd appreciate rigorous criticism. If this framework fails, I'd like to know exactly where. If it resembles existing work in category theory, type theory, domain theory, or another area, I'd also appreciate references.

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u/Arlo_Tinkerman — 2 months ago

Why Every Fraction Already Has a Matching Whole Number

We are taught to treat the decimal point as a wall.

To the left, whole numbers march outward without end. To the right, fractional numbers divide inward without end.

<--- whole numbers --- 493.538 --- fractional numbers --->

The two directions feel like different worlds, and for more than a century the standard way of relating them has been to build elaborate grids and draw diagonal paths through them.

Yet the ordinary machinery of place value already contains a simpler relationship. When the basic engine that generates the whole numbers is coupled to a local fact about positional notation, the two sides of the decimal point turn out to be locked together more tightly than the usual picture suggests.

  1. The Generative Engine of the Wholes

Start with the most ordinary fact in arithmetic.

The whole numbers are generated by repeated application of a single operation:

N → N + 1

Each application produces a new, distinct whole number. There are no gaps and no omissions. The entire open-ended sequence of magnitude is unfolded by this one iterative rule. This is not a philosophical claim. It is the constructive definition of the natural numbers that every mathematician already accepts.

  1. The Local Positional Tether

Now set the generative process aside for a moment and look only at place value itself.

In any positional system there is a direct, base-agnostic correspondence between a digit’s fractional place and a corresponding integer place:

[N × B^(–P)] ↔ [N × B^(P–1)]

Where

- N is the digit

- B is the base

- P is the positional index measured from the radix point

In base 10 the mapping is immediate:

- 0.2 (tenths) ↔ 2

- 0.05 (hundredths) ↔ 50

- 0.008 (thousandths) ↔ 800

So the fractional number 0.258 reflects position-by-position into the integer 852.

The same relation holds in every base. In binary, 0.101 maps component-wise to 101. The correspondence depends only on the exponents. It is therefore independent of the particular radix chosen.

At every finite depth P the tether is exact. No additional machinery is required.

  1. Coupling and Pre-Emptive Blocking

The two components can now be joined.

The successor operation N + 1 is the engine that exhausts the wholes.

The positional tether is the rule that, at every index P, immediately supplies a matching whole for any part that can be written.

Any part that can be indicated already carries a positional index P. The moment that index is present, the tether formula activates and produces the corresponding whole. There is no delay and no extra step. The common escape, to suppose that there might exist parts that simply lack corresponding wholes, is blocked before it can begin. To assert an unmatched part one would have to exhibit a digit that possesses no place-value index P. That is a contradiction inside positional notation itself.

Once the escape is closed, and once N + 1 is granted as the process that exhausts the wholes, the two sides stand in exact equilibrium. Every whole forces a part mirror. Every addressable part already requires a whole mirror. No residual unmatched part remains possible.

Conclusion

* First — The successor engine generates the entire sequence of whole numbers.

* Second — The positional tether assigns every addressable fractional position a corresponding whole-number position.

* Together — They leave no structural gap between the two sides of the decimal point.

The decimal point therefore does not separate unrelated number spaces. It marks the line of a positional mirror. As the whole-number side extends outward through counting, the fractional side extends inward in matching order. The two sides are mirror-locked.

---------------

Also posted to Medium. Multiple posts planned for a series about infinity.
LINK: https://medium.com/@arlotinkerman/why-every-fraction-already-has-a-matching-whole-number-7ca627dc98c7

u/Arlo_Tinkerman — 2 months ago
▲ 1 r/InfinityMath+1 crossposts

👋 Welcome to r/InfinityMath: Bring Your Proofs, Questions, and Objections

Hey everyone! I'm u/Arlo_Tinkerman, the founding moderator of r/InfinityMath.

This is a place to explore infinity from every mathematical perspective.

Cantorian, constructivist, finitist, ultrafinitist, undecided, or developing something new, all are welcome here. The point is not to gather only people who already agree. The point is to put different ideas into contact with each other and see which arguments hold up.

Infinity is one of those subjects that can get people surprisingly worked up. It sits underneath set theory, number systems, limits, geometry, calculus, logic, and the foundations of mathematics. It also raises basic questions that are easy to state but difficult to settle.

  • What does it mean for something to be infinite?
  • Can an infinite collection be complete?
  • Is infinity actual, potential, or something else?
  • What does it mean to account for all members of an unending sequence?
  • How should whole numbers, fractions, decimals, limits, and sets be understood in relation to infinity?

Those questions are open for discussion here.

What to Post

You are welcome to post:

  • Proofs and proposed proofs
  • Objections to established or alternative views
  • Questions about infinity
  • Arguments involving actual or potential infinity
  • Discussions of Cantorian set theory
  • Constructivist, finitist, or ultrafinitist approaches
  • New mathematical frameworks or interpretations
  • Explanations of difficult ideas
  • Historical material about infinity
  • Diagrams, models, or thought experiments
  • Requests for criticism or review

I will also be sharing some of my own work here. My current project examines infinity through generative systems, whole-number counting, fractional structure, positional notation, and what I call the prime extent. I do not expect anyone to accept those ideas merely because I post them. I want people to inspect the definitions, premises, operations, and inferential steps.

The same standard should apply to every position, including established ones.

Community Vibe

Disagreement is expected. Hostility is not required.

Criticize the argument rather than the person making it. Try to explain where an argument fails instead of merely labeling it wrong. When possible, identify the specific premise, definition, equation, or inferential step you reject.

Likewise, anyone presenting a new idea should expect serious objections. A strong challenge is useful when it exposes an error, forces a definition to become clearer, or reveals that two people are using the same word differently.

The goal is not enforced agreement. The goal is stronger ideas through serious discussion.

How to Get Started

  1. Introduce yourself in the comments and mention what interests you about infinity.
  2. Share a question, proof, objection, diagram, or argument.
  3. Invite someone who would contribute thoughtfully, including someone who may disagree with you.
  4. Let me know if you are interested in helping moderate as the community grows.

Thanks for joining at the beginning. I hope this becomes a place where people can question familiar assumptions, defend established mathematics, propose alternatives, and sharpen one another's thinking.

reddit.com
u/Arlo_Tinkerman — 2 months ago
▲ 1 r/InfinityMath+1 crossposts

My own reasoning about infinity divided by infinity — would love feedback (Class 12 student)

A Proposal for a Context-Specific Interpretation of "Infinity Divided by Infinity"

Author: Ritesh Wankhede

Abstract

This paper proposes a specific way to interpret the expression "infinity divided by infinity." It does not claim standard mathematics is wrong. It presents one interpretation, valid only under clearly stated conditions.

The core idea: when infinitely many objects are matched to infinitely many recipients so that every recipient gets exactly one object and every object goes to exactly one recipient, the distribution can be understood as one object per recipient — within that specific matching.

  1. The Question

If infinitely many objects are distributed among infinitely many recipients, with each recipient getting exactly one object and no object left over, what does that distribution represent?

  1. What "Infinite" Means Here

For this proposal, infinite means a collection that never ends — like the counting numbers 1, 2, 3, 4, 5, ... — with no final number.

  1. The Setup

Assume:

There are infinitely many people.

There are infinitely many chocolates.

Every person receives exactly one chocolate.

Every chocolate goes to exactly one person.

  1. The Example

Person 1 gets Chocolate 1.

Person 2 gets Chocolate 2.

Person 3 gets Chocolate 3.

This continues forever: Person n always gets Chocolate n.

No chocolate is shared between two people. No person goes without.

  1. The Reasoning

With finite numbers, if 100 chocolates are split evenly among 100 people, each person gets exactly one. This proposal simply extends that same idea to the infinite case above: since every person is matched to exactly one chocolate, the natural reading of the distribution is one chocolate per person.

  1. The Proposed Interpretation

This does not claim "infinity divided by infinity always equals one" as a general rule.

It claims something narrower: when infinite objects are matched to infinite recipients so that each side is used exactly once, that specific matching can be read as one object per recipient.

  1. Where This Does NOT Apply

This idea is limited to the exact matching described above. It is not claimed to apply to:

Calculus or limits involving infinity

Every possible way of pairing two infinite collections

Every mathematical system

Other ways of matching the same two infinite groups might not give this same "one-to-one" feel — that's a real limitation, and I don't yet have a way to resolve it. It's part of what I want feedback on.

  1. Open Questions

Is there a rigorous way to express this idea?

Does the interpretation change if the matching rule between people and chocolates changes?

Can this idea be pushed further without leading to contradictions?

  1. Conclusion

When infinitely many objects are matched one-to-one with infinitely many recipients, each recipient receives exactly one object. Within this specific matching, the distribution corresponds to one object per recipient. This is offered as a starting idea for discussion, not a finished theorem.

Author's Note

I'm a Class 12 student from Mumbai with a strong interest in mathematics. I know this connects to ideas already studied by mathematicians, and I'd like to learn where my reasoning holds up and where it needs refining.

reddit.com
u/AncientDatabase159 — 2 months ago
▲ 2 r/InfinityMath+1 crossposts

Does 0.999 (repeating) = 1? Well, "it depends"

"Is 0.999.. with a infinite number of 9's equal to 1" has sparked a number of online debates. I believe the crux of the debate is the question is not worded precisely enough. There are different notions of infinite which lead to different answers. Adding to the confusion, "0.999..." is math notation with a specific meaning, but some people aren't thinking of that when they use it in a sentence.

Below are my two proofs for "Does 0.999 (repeating) equal one?" using less ambiguous notions of infinity. The answer is that it does and it doesn't but you need to be specific about what you mean in a way that we aren't used to.

"0. followed by a specific but infinitely large integer number (H) of 9's"**

I will denote this quantity as 0.{H 9's}. This is LESS than 1.*

Proof:

  1. Assume two numbers** are equal if and only if their difference is zero
  2. Therefore 0.{H 9's} is 1 if and only if abs(1 - 0.{H 9's}) = 0
  3. Consider a specific but infinitely large integer** value of H
  4. There exists H+1
  5. And abs(1 - 0.{H 9's}) &gt; abs(1 - 0.{H+1 9's})
  6. This implies abs(1 - 0.{H 9's}) &gt; 0
  7. (1.) and (6.) imply 0.{H 9's} is not 1

Unsatisfyingly, this doesn't prove things like "The concept of H is valid", or "H < a different notion of infinity", "H+1 &gt; H", or "H+1 exists". If you want to read up on this, look up hyperreal numbers, hyperintegers, and nonstandard analysis.

"0. followed by a 9 for every standard natural number"

I will denote this quantity as 0.999... . This is EQUAL to one. I think this is what most people think of when they hear "0.999 repeating infinitely".*

Proof:

  1. Assume two numbers** are equal if and only if their difference is zero
  2. Therefore 0.999... is 1 if and only if abs(1 - 0.999...) = 0
  3. Assume that abs(1 - 0.999...) is a positive number**
  4. Consider a specific nonzero positive number** H
  5. There exists a number of nines in 0.999... such that abs(1 - 0.999...) &lt; H
  6. (1.) and (5.) imply abs(1 - 0.999...) is not H
  7. (4.) and (6.) imply abs(1 - 0.999...) is not a nonzero positive number**
  8. The only positive number that is not a nonzero positive number** is zero
  9. This implies abs(1 - 0.999...) is zero
  10. (1.) and (9.) imply 0.999... = 1

Unsatisfyingly, this doesn't prove "0.999... always has enough nines to make abs(1 - 0.999...) &lt; H". If you want to read up on this, look up hyperreal numbers, hyperintegers, and nonstandard analysis.

...Its been a long time since I wrote a proof ...Im sure some of my wording isn't great ...I wanted to make this semi-readable for "common folk"...

*There is a better way to write 0.{H 9's} and 0.999... but I can't write it here because it requires LaTeX formatting.

**"number" should be replaced with "hyperreal number" and "integer" should be replaced with hyperinteger" but I wanted to make the proof readable to people who don't know what those are.

reddit.com
u/Arlo_Tinkerman — 2 months ago
▲ 3 r/InfinityMath+1 crossposts

Help me understand an infinite universe

Although I know the science that the universe is infinite if it's flat or saddle shaped and may not be if it's closed curved, I can't understand infinity when I consider a simple thought experiment. I would really appreciate help from anybody who can align my brain with reality.

In my thought experiment, before the Big Bang, everything is just a singularity sitting in one point. Ignoring heat, lack of visibility, etc I can imagine the universe exploding and after 1 second it is some size larger than the singularity.. for the sake of argument let's say it has expanded 100 miles in each direction..

So now we have a sphere with a radius of 100 miles.

Obviously the earth doesn't exist yet, but let's assume that the cosmic ingredients for our solar system are halfway between the center starting point and the hundred miles to the edge of the sphere that we're inside of. Let's let's put a point on the inside edge of the sphere, the edge of the universe and nothing, and call it x.

X is currently 50 miles away in one direction and the center of the universe is 50 mi in the opposite direction.

Time goes on, the bubble keeps expanding and at some point our solar system has formed and we're here and we can look out.

We may not be able to see x because it could have moved away from us faster than the speed of light.

However from my previous thinking, it seems logical that there is a distance to x, which in this case might be half of the radius of the universe at this point in time.

Or maybe the expansion is faster farther away at point x so maybe the scale is wrong.. maybe the stuff earth was made from is closer to the center than it is to x at this point.

But if we consider the uneven rates, we should still be able to say x is this distance and the center of the universe is y distance.

Of course I'm not considering any other variables like uneven density or anything else.

I also know of the analogy that we are on the skin of a balloon that is being blown up, but once again the distance of that skin from the originating point seems like it would also give us a distance.

There's another analogy that seems appropriate.. one of the ways that we can prove tectonic movement is to measure the increase of distance of Europe from America every year... Measure how far they have moved away from the Mid-Atlantic fault and do the math to understand how long ago the two separated from the falt.

So why can't we run the math backwards just like we did with plate tectonics to figure out how far everything has moved?

I know I'm missing something big, what is it?

reddit.com
u/Arlo_Tinkerman — 2 months ago
▲ 12 r/InfinityMath+1 crossposts

Why does infinity work perfectly in math—but break physics?

In mathematics, infinity is not treated as a vague or mystical idea—it is a fully structured concept.

We don’t just say “infinity exists” as a single thing. Mathematics actually refines it into different forms. In set theory, for example, there are different sizes of infinity. The set of natural numbers is infinite, but the set of real numbers is a strictly larger type of infinity. This leads to a hierarchy of infinities, where some infinities are provably bigger than others.

So in math, infinity is not a failure or an edge case—it is something that can be rigorously defined, compared, and explored inside a consistent logical system.

Physics, however, seems to treat infinity very differently.

When infinities appear in physical theories, they are almost never accepted as “real answers.” Instead, they are usually treated as warning signs that something has gone wrong in the model.

For example:

  • In general relativity, black hole singularities produce infinite density.
  • In quantum field theory, certain calculations initially produce divergent (infinite) results.
  • In many cases, physicists introduce techniques like renormalization to remove or reframe these infinities so that meaningful finite predictions emerge.

So in physics, infinity is often not the endpoint of understanding—it is usually a signal that the theory is being pushed beyond its valid range.

This creates a really interesting contrast.

In mathematics:

  • Infinity is structured.
  • Infinity is classified.
  • There are multiple infinities with precise relationships between them.

In physics:

  • Infinity is usually problematic.
  • It often indicates a breakdown of the theory.
  • It is something to be removed, regulated, or replaced.

Yet despite this difference, mathematics and physics are otherwise extremely tightly connected. In almost every other domain—calculus, differential equations, geometry, linear algebra, symmetry theory—mathematics provides the language of physics, and physics often guides new mathematical development.

Which makes infinity stand out as one of the rare points where the connection feels less direct or at least less “clean.”

This leads to a deeper question:

Is this because mathematics is dealing with a purely abstract concept of infinity that is not meant to correspond directly to physical reality?

Or is it because the infinities we see in physics are not “real infinities,” but instead signs that our current theories are incomplete, and that a deeper framework might eventually remove them entirely?

Or, more fundamentally, are mathematical infinity and physical infinity actually different kinds of concepts that only share the same name, but not the same meaning?

Because in a strange way, it almost feels like:

  • Mathematics is comfortable exploring infinity as a fully defined structure.
  • Physics is only comfortable with infinity when it can be eliminated or interpreted away.

So why is infinity one of the very few concepts where mathematics and physics seem to diverge so sharply in interpretation, despite their otherwise extremely deep and successful relationship?

reddit.com
u/Arlo_Tinkerman — 2 months ago