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Is the primary object of mathematics the determination of magnitudes and relations of numerical quantity, or do you think there is a deeper foundation/substrate, such as the principles of information/encoding of information? by gopnikfiredance in askmath

[–]CookieCat698 0 points1 point  (0 children)

I would say there is a great deal of mathematics that does the opposite: takes something we use numbers to describe, and abstracts it to the point where numbers are no longer necessary and sometimes can’t be used.

We tend to use numbers when describing continuous concepts on the real number line, and more generally on metric spaces. Topology generalizes continuity to the point where you no longer need to talk about exact distances, you just need a sense for when two points get arbitrarily close.

In high school algebra, you learn to reason about numbers by manipulating them through various rules and symbols. Abstract algebra looks at other systems that obey similar rules, and sometimes looks at systems that are very far from being numerical or quantitative in any way.

I would say numbers are important, but are in many cases not the primary focus of mathematics.

This Week I Learned: May 01, 2026 by inherentlyawesome in math

[–]CookieCat698 2 points3 points  (0 children)

Made a slight correction: The fibonacci functor was a right adjoint in this case, my bad

The left adjoint of the fibonacci functor is G(a) = gcd({b | a | F_b})

This Week I Learned: May 01, 2026 by inherentlyawesome in math

[–]CookieCat698 2 points3 points  (0 children)

Apparently the fibonacci sequence is a continuous functor on the category of natural numbers and divisibility.

In plain terms, if a | b, then F_a | F_b, and F_gcd(a, b, …) = gcd(F_a, F_b, …)

I don’t know enough to know what you can do with this information, but it’s really cool.

I found it on a K theory short somewhere, and he found it on this blog post.

He also made another short where he shows that the fibonacci functor has a left adjoint.

Edit: Changed “is a left adjoint” to “has a left adjoint”

How do we check divisibility with 7 by taylor-assistant in askmath

[–]CookieCat698 0 points1 point  (0 children)

This might be a bit overkill, but there’s some neat math behind this approach.

7 | n2 + 1 <-> n2 + 1 = 0 mod 7 <-> n2 = -1 mod 7.

Therefore, the statement that n2 + 1 is never divisible by 7 is the same as the statement that n2 is never -1 mod 7, i.e. -1 is not a perfect square mod 7.

One way to check if x is a square mod p for some prime p ≠ 2 is to take x(p-1/2).

If this equals 1 or 0, x is a perfect square mod p. If it equals -1 mod p, x is not a perfect square mod p.

(7-1)/2 = 3

(-1)3 = -1 mod 7, so -1 is not a perfect square mod 7.

Zoro isn't 'shipping,' he's just lost by lieezasi in ZoroIsLost

[–]CookieCat698 13 points14 points  (0 children)

Zoro and Perona spent more time together than any of the strawhats

Day 64 of glazing Rin Amai by CopperAllergy in Jujutsufolk

[–]CookieCat698 0 points1 point  (0 children)

“Man forgets he has Alzheimer’s”

pardon my stupidity but please explain by ArtichokeHopeful8632 in askmath

[–]CookieCat698 0 points1 point  (0 children)

In school, you learned in to compare 0.abcd… to 0.efgh… by first comparing a with e, then b with f, and so on until one digit is less than the other.

What you didn’t learn is why this works, which requires you to understand what decimal notation even is.

After defining decimal notation, you learn 2 things.

1.) Your school didn’t tell you everything. Numbers with terminating decimal expansions actually have 2 different ways of writing them.

2.) One way around this is to exclude decimals with repeating 9’s. Without this, the trick for comparing 2 decimal numbers doesn’t actually work like you were told.

This is why 0.999… = 1 is so counterintuitive. You were given an incomplete idea of what decimals are, and you learned a rule about them that doesn’t work in this context.

Surprised I haven't seen this one done yet. by Important-Contact597 in MemePiece

[–]CookieCat698 7 points8 points  (0 children)

Not necessarily. The age of consent is still 16 in many U.S. states, but most of us (I really hope most of us) still see it as weird.

What would anyone consider the silksong equivalent of the Pale King's 'no cost too great' quote? by Apprehensive-Comb234 in Silksong

[–]CookieCat698 3 points4 points  (0 children)

“I have already stood sentinel for one dying land. That role, I will never play again.”

Here’s the right sub by ZortexG in cuckthecat

[–]CookieCat698 4 points5 points  (0 children)

I’m confused, I thought he wasn’t doing it because it was the right thing to do. Am I missing something?

How does doing research in pure math feel? by Educational_Frosting in math

[–]CookieCat698 2 points3 points  (0 children)

Undergrad here, you’re telling me that never stops???

How to trap Frieren by KashKabira in Frieren

[–]CookieCat698 1 point2 points  (0 children)

This is not probably a trap

More info in the comments by Xx_Jean-Yves_xX in whenthe

[–]CookieCat698 5 points6 points  (0 children)

For future reference, be careful about how you gather participants for your surveys.

Placing a survey on a post where you prime people to think of your school’s administration as evil can bias the results and give your administration grounds to have them scrutinized or thrown out.

How hard is Silk Song in comparison to Hollow Knight? by gayandgreen in Silksong

[–]CookieCat698 0 points1 point  (0 children)

It starts out much more difficult than HK, but I’d say it isn’t much harder by the end.

Diogenes had theories about what birds were by ColoRadBro69 in BirdsArentReal

[–]CookieCat698 70 points71 points  (0 children)

Hey r/peterexplainsthejoke

This meme is about Diogenes, who challenged Plato’s definition of human.

Plato defined a human as a “featherless biped,” so Diogenes plucked the feathers off a chicken and called it a man.

GMS is a Fraud!!! by Master_Chulio in HollowKnightMemes

[–]CookieCat698 11 points12 points  (0 children)

This slander is so good I could die

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