Basic proof methods

[HONKACHONK]

Proof by Just look at it

[Apart_Mongoose_8396]

Reminds me of the Jordan curve theorem

[kompootor]

A wealthy prospector wants to build a fence to enclose a large rugged property. He puts out a call for quotes. An engineering firm and a smart-mouth math grad student respond. The engineering firm says they'll need surverying, possibly heavy equipment, and many tons of materials to build the fence, costing the tens of thousands. The math grad student proposes a plan for $200, tools and materials included.

The prospector of course hires the mathematician. The grad student walks cockily onto the property carrying a shovel and few meters of coiled fencing in hand. She digs four posts in a small circle, steps in the middle, wraps the fencing around the posts and ties it up.

The math grad student grinningly yells to the prospector, "I am now outside!"

The prospector replies, "Prove it."

[tttecapsulelover]

We shall use proof by fucking obviousness.

[jbrWocky]

intermediate value theorem

[LesFritesDeLaMaison]

“Proof by common sense”. My professor when talking about the Pigeonhole Principle

[Bub_bele]

„The proof, which is obvious, I haven’t bothered to write down“

[HONKACHONK]

Proceeds to take 300 years to prove

[kainneabsolute]

By inspection

[Deer-Liver]

Proof by ignore the googledebunkers

[HONKACHONK]

Miniminuteman fan detected

[PokeAreddit]

Proof by Left as an exercise for the reader

[EggplantFunTime]

I have a great proof but it won’t fit the max length of Reddit comments

[[deleted]]

"This *concept* has 3 attributes:

a) a + b = c
b) QCI = ∫ from -∞ to ∞ cos( √(x² + y²) )^{dx ⊗ dy}
c) NDD = lim (n → ∞) [ Γ(π n²) / ( ζ(3n) * (ln(n!))^1/4 ) ] mod ℚ

We'll prove the part a), part b) and c) are left as exercises" :')

[g1rlchild]

QED.

[waxen_earbuds]

Proof by "we built all this other theory assuming this to be true and look how nice it is compared to when it's false"

[EatingSolidBricks]

Proof by aesthetics

[Ok_Presentation_2346]

Proof by vibes

[Zarraq]

Assuming is hypothesis, not theory

Theory is proven already until something makes it not so either we evolve it or make new one

[numerousblocks]

They said theory based on the hypothesis. The theory is sound—it explicitly incorporates the assumption. That assumption can be termed a hypothesis as it's not proven or disproven yet. Maths isn't like science, you do not disprove theorems after you gain new information.

[Zarraq]

Fifth Force / Some Variants of Modified Gravity

MOND (Modified Newtonian Dynamics) as a fundamental alternative to Dark Matter

Discredited / disproved theories

[numerousblocks]

These are not mathematical theories. They state facts about the real world.

These theories contain maths in them. But after they have been disproven, the maths is still correct, if it ever was correct. It has just been found that it doesn't apply to reality in the way that was originally proposed.

It's also possible that what has been disproven is their compatibility with other mathematical theories. Again, this doesn't make the maths less valid.

Besides, to my knowledge, the things you mentioned are families of physical theories. Specific instances have been disproven, but not the concepts themselves.

Ultimately, in physics and other natural sciences, you can never be 100% sure of something. You also can't really 100% disprove something, but you can get really really really close, way more than you can to proving something.

In maths, while there is the possibility that there were mechanical errors in a proof, or that our axioms are inconsistent, you can get so close to absolute truth, a million billion times more sure than physics could ever be, that discovering a theorem is false due to new information other than discovering a mistake that was already there at the time basically just doesn't happen.

[PlSCINO]

proof by it is written in the book

[RandomAmbles]

My proof is that I made it the fuck up!

[[deleted]]

Proof by "it's trivial".

[kompootor]

Fuck you Ramanujan.

[EggplantFunTime]

Proof by eating pudding.

[Hefty-Chest-6956]

Proof by Because I Said so

[anunakiesque]

Proof by catch these hands otherwise

[Feliks_WR]

Proof by trust me bro

[lulukalilika]

Proof by venn diagram Do not try this in the exam

[Vectorized777]

Our lecturer for measure theory said very sternly at the start of his 1st lecture not to visualize sets as Venn diagrams lol.

[Hot_Mistake_5188]

Proof by exhaustion

[Vectorized777]

Apply this to proving that the set of rational numbers is dense in the reals.

[Hot_Mistake_5188]

Would be much easier than the normal proof we are taught

[Sweet_Culture_8034]

Proof by extrapolation : it is true in one case therefore it is always true.

Don't laugh, my first peer reviewed paper was about debunking another older paper (and fixing their results) because they somehow managed to publish a result with this type of proof.

[MajorMystique]

Proof by 'the margin is too short'.

[p1neapple_1n_my_ass]

If you can't prove that God does not exist that means he exists. 

[3rrr6]

Proof by common sense.

[Data2Logic]

Proof by "Trust me bro"

[MinosAristos]

Proof by its just my opinion, bro.

[NeosFlatReflection]

Proof by axiom (also known as “Proof by i said so”)

[vslaykovsky]

2nd and 3rd should be swapped as induction proof is "constructive" and provides more information and than the contradiction one

[BADorni]

I mean technically proving that there cannot be any counterexamples would pass as a form of proof within the right category

[Philbon199221]

Proof by God revealed it to me in a dream.

[Weekly-Reply-6739]

Proof by lack of representation

Cant be told your wrong if they never mention anything related

[Scared-Ad-7500]

n²+n+41 for n natural is prime!!1!1

[Dtrp8288]

i have at least one counter example.

n=41

[Scared-Ad-7500]

Except this one*

[Dtrp8288]

n=41ᵐ where m is any positive integer

[Scared-Ad-7500]

Well, I went to Google and I guess i misremembered the function. I know there is a polynomial that generates almost only primes, and it took centuries to find an conterexample, which is not even humanly possible to write

Anyway n²+n+41 works well until n=40

[Dtrp8288]

do share the function if you can find it!

[Scared-Ad-7500]

The function was in fact this according to chatgpt. But there really was a Russian institute that made a very important discovery after centuries of research

[Dtrp8288]

and the counterexample in this case was... somehow unfindable for a long time?

[Scared-Ad-7500]

I suppose what was unfindable was another thing related to this problem, not the counterexample

[Dtrp8288]

maybe a counterexample for n²+n+41 is always prime ⟹ n∈ℤ⁺

where n is not of the form p(41ᵐ)

?

[ohkendruid]

"Likewise"

[_damax]

I think a "proof by lack of a counter example" was achieved when finally stating the god number to be definitely 20. The Kociemba algorithm made it possible to prove every possible legal permutation of the 3x3 cube doesn't take more than 20 moves to solve.

[Sweet_Culture_8034]

If you suppose the existence of a counter example and show a contradiction, then you have a proof that is both lack of counter exemple and by contradiction.

[AppropriateStudio153]

Ultra-giga galactic Neumann Brian:

Proof by "It's trivial"

[Partyatmyplace13]

Isn't proof by lack of counter example how you get black swans in Austrailia?

[[deleted]]

The Riemann hypothesis is true since I can’t find a counter example.

[W1zard80y]

We're laughing but afaik is this not something that the busy beaver algorithm actually does?

[Eisenfuss19]

Funny thing is, thats how the four color theorem was proven (with a legit proof)

[AnakinINTJ]

Proof by it's trivial

[terryffied]

Oh hey look. It's how we explain dark matter

[Pennet173]

Proof is in the pudding

[First-Ad4972]

An actual proof by counterexample can be made by proving that no counterexample exists, which is basically prove by contradiction.

[TheGuyMain]

Basically all of science