Mathematics

50%

+0 −0

Introducing a dependent function in the metalanguage without pi-types

0 answers · posted 10d ago by user205‭ · edited 10d ago by user205‭

type-theory

71%

+3 −0

Is there a $\Delta$-complex structure on the sphere with less than three $0$-simplices?

1 answer · posted 23d ago by The Amplitwist‭ · last activity 18d ago by Derek Elkins‭

algebraic-topology delta-complex

22%

+0 −5

What are the Peano axioms?

1 answer · posted 3mo ago by Julius H.‭ · last activity 2mo ago by rmf‭

logic

50%

+3 −3

Defining Bayes’s theorem from scratch in ZFC

1 answer · posted 3mo ago by Julius H.‭ · last activity 1mo ago by xamidi‭

set-theory zfc bayes-theorem

50%

+1 −1

What are the “increasingly stable consequences of the large cardinal hierarchy”?

0 answers · posted 3mo ago by Julius H.‭

set-theory

66%

+2 −0

A program which could derive theorems given formation rules in any modal logic?

1 answer · posted 3mo ago by Julius H.‭ · edited 3mo ago by Peter Taylor‭

computational-mathematics proof-assistants

60%

+1 −0

How do I unambiguously define the facial circuits in a $2$-cell embedding of a graph into a surface?

0 answers · posted 20d ago by The Amplitwist‭ · edited 17d ago by The Amplitwist‭

topology graph-theory

66%

+2 −0

The Fourier transform of $1/p^3$

1 answer · posted 2mo ago by C-T‭ · last activity 2mo ago by LL 3.14‭

complex-analysis calculus multivariable-calculus integration fourier-analysis

60%

+1 −0

$\liminf (a_n+b_n) = \liminf(a_n)+\liminf(b_n)$ provided that $\lim a_n$ exists

1 answer · posted 4mo ago by Snoopy‭ · edited 4mo ago by Snoopy‭

real-analysis

66%

+2 −0

Does {7,4|3} have a realization on the Klein quartic?

0 answers · posted 2mo ago by WheatWizard‭

polytopes algebraic-geometry

66%

+2 −0

For any real number $m$, $ \left|\sum_{n=1}^{\infty}\frac{m}{n^2+m^2}\right|<\frac{\pi}{2} $

1 answer · posted 4mo ago by Snoopy‭ · last activity 4mo ago by Snoopy‭

calculus real-analysis

44%

+2 −3

Cyclical or “loop” fractals?

1 answer · posted 3mo ago by Julius H.‭ · last activity 3mo ago by r~~‭

real-analysis fractal

50%

+0 −0

The effect of measurement accuracy and rounding on hypothesis testing

0 answers · posted 14d ago by tommi‭ · edited 14d ago by tommi‭

statistics hypothesis-testing rounding

71%

+3 −0

Besov or Triebel-Lizorkin spaces versus Lorentz spaces

0 answers · posted 2mo ago by LL 3.14‭ · edited 2mo ago by LL 3.14‭

interpolation Besov-space functional-analysis

60%

+1 −0

Seeking a theorem about lattices

1 answer · posted 10d ago by WheatWizard‭ · last activity 5h ago by Lisanne‭

linear-algebra reference-request free-abelian-group

60%

+1 −0

Why is $ \int_0^{\infty}\left|\frac{\sin x}{x}\right|\ dx=\infty$?

1 answer · posted 4mo ago by Snoopy‭ · last activity 4mo ago by Snoopy‭

real-analysis improper-integral

42%

+1 −2

Explain derived categories to someone without a strong background in homological algebra [closed]

0 answers · posted 3mo ago by Julius H.‭ · closed 3mo ago by Peter Taylor‭

category-theory

66%

+2 −0

Find length $MP$ in trapezoid

0 answers · posted 2mo ago by TheCodidacter, or rather ACodidacter‭ · edited 2mo ago by TheCodidacter, or rather ACodidacter‭

geometry

66%

+2 −0

matrix inverse of $I + A$ where $A$ is skew-symmetric

1 answer · posted 3mo ago by Trevor‭ · last activity 3mo ago by Trevor‭

linear-algebra

37%

+1 −3

Solely by eye, how can 16 year olds visually distinguish $\color{red}{\vec{b} - \vec{r}}$ from $\color{limegreen}{|\vec{b}| - |\vec{r}|}$ ?

2 answers · posted 8mo ago by Tortilla‭ · last activity 8mo ago by Olin Lathrop‭

visualization

66%

+2 −0

$\sup(A\cdot B) = (\sup A)(\sup B)$ where $A$ and $B$ bounded sets of positive real numbers

3 answers · posted 4mo ago by Snoopy‭ · edited 4mo ago by Snoopy‭

real-analysis supremum-infimum

60%

+1 −0

What does it mean by saying that $C([0,1])$ is a subset of $L^\infty([0,1])$?

1 answer · posted 4mo ago by Snoopy‭ · last activity 4mo ago by Snoopy‭

real-analysis

33%

+1 −4

Without trial and error, how can I effortlessly deduce all $n, k_i ∈ ℕ ∋ \binom n {k_1, k_2, ..., k_n} =$ given c?

1 answer · posted 9mo ago by Chgg Clou‭ · edited 9mo ago by Chgg Clou‭

combinatorics

62%

+3 −1

Minimal non-standard number in non-standard models of PA

1 answer · posted 3mo ago by Aditya‭ · edited 3mo ago by The Amplitwist‭

logic model peano-arithmetic nonstandard-models

33%

+1 −4

How to decide whether to buy a lottery with a too negative EV, but passable $\Pr($you win jackpot at least once│n plays)? [closed]

0 answers · posted 10mo ago by Chgg Clou‭ · edited 10mo ago by Chgg Clou‭

lottery

42%

+1 −2

What is the significance of the K-axiom in modal logic S5?

1 answer · posted 2mo ago by Julius H.‭ · edited 29d ago by xamidi‭

modal-logic proof-theory hilbert-systems axioms

80%

+6 −0

Criteria for solvable Minesweeper game?

0 answers · posted 10mo ago by Olin Lathrop‭ · edited 10mo ago by Olin Lathrop‭

algorithm

66%

+2 −0

Is the nth Betti number determined by orientability?

1 answer · posted 6mo ago by WheatWizard‭ · edited 5mo ago by WheatWizard‭

betti-numbers algebraic-topology

66%

+2 −0

The derivatives of a function at a boundary point

1 answer · posted 4mo ago by tommi‭ · last activity 4mo ago by Snoopy‭

derivatives real-analysis

44%

+2 −3

How to compare lotteries, when one has highest probability of winning the jackpot, but another the highest Expected Value?

1 answer · posted 11mo ago by Chgg Clou‭ · last activity 11mo ago by tommi‭

lottery

71%

+3 −0

Is it possible to show that a normalised random variable has zero mean and unit variance?

0 answers · posted 8mo ago by mr Tsjolder‭ · edited 8mo ago by mr Tsjolder‭

statistics expectation

42%

+1 −2

1 picture proof for the triangle inequality and the reverse triangle inequality

0 answers · posted 9mo ago by Este‭ · edited 9mo ago by trichoplax‭

visualization

66%

+2 −0

Fourier transform of an $L^1$ function is uniformly continuous

1 answer · posted 3mo ago by Snoopy‭ · edited 3mo ago by Snoopy‭

real-analysis fourier-analysis

71%

+3 −0

If both $\lim_{x\to\infty}f(x)$ and $\lim_{x\to\infty}f'(x)$ exist, then $\lim_{x\to\infty}f'(x)=0$.

1 answer · posted 4mo ago by Snoopy‭ · last activity 4mo ago by Snoopy‭

real-analysis

66%

+2 −0

Is it possible to find a solution for any $ae^{bx}+cx+d=0$?

0 answers · posted 7d ago by CrSb0001‭

calculus recreational-mathematics

66%

+2 −0

Concrete examples of set theorists thinking independence proofs only determine provability rather than that a statement is neither true nor false?

1 answer · posted 3mo ago by Julius H.‭ · last activity 3mo ago by Peter Taylor‭

set-theory

50%

+1 −1

Prove that $\forall x\in\Bbb R:\lfloor x^2\rfloor-\lfloor rx\rfloor\ge-1\iff|r|\le2$.

1 answer · posted 1mo ago by TheCodidacter, or rather ACodidacter‭ · last activity 1mo ago by Derek Elkins‭

inequality solution-verification

66%

+4 −1

is arithmetic finitely consistent?

0 answers · posted 3mo ago by Jason‭

proof logic peano-arithmetic incompletness consistency

60%

+1 −0

Obtaining the semantics of simple type theory as a particular case of the set-theoretic semantics of dependent type theory

0 answers · posted 16d ago by user205‭ · edited 16d ago by user205‭

constructive-logic type-theory logic

28%

+0 −3

What is a dual object? [closed]

0 answers · posted 3mo ago by Julius H.‭ · closed 3mo ago by Peter Taylor‭

category-theory

37%

+1 −3

Why do the Expected Values differ, for different wagers of the same lottery?

1 answer · posted 10mo ago by Chgg Clou‭ · last activity 10mo ago by Peter Taylor‭

lottery

28%

+0 −3

What is a “first-order substructural logic that has a cut-free sequent calculus”?

1 answer · posted 2mo ago by Julius H.‭ · last activity 2mo ago by Dan Doel‭

logic

42%

+1 −2

How to intuit P(win the same lottery twice) $= p^{2}$ vs. P(win the same lottery twice | you won the lottery once) $= p$?

2 answers · posted 1y ago by Chgg Clou‭ · edited 1y ago by Chgg Clou‭

lottery

40%

+0 −1

While pictorializing $|x - y| < |x + y|$, how can 1 picture simultaneously prove (Reverse) △ Inequalities, $|x-y| ≤ |x|+|y|, |x|-|y| ≤ |x-y|$? [duplicate]

0 answers · posted 8mo ago by Tortilla‭ · closed as duplicate 8mo ago by Peter Taylor‭

visualization

60%

+1 −0

Defining the two universes from Calculus of Constructions in LF

0 answers · posted 1y ago by user205‭ · edited 1y ago by user205‭

type-theory logic

60%

+1 −0

Is there a "regular" quasi-convex function $f:\Bbb R^2 \to \Bbb R$ that is not a monotone transformation of any convex function?

0 answers · posted 1y ago by Pavel Kocourek‭

multivariable-calculus real-analysis convex-analysis monotone-functions

50%

+0 −0

Finding a quadratic that has solutions to given values

1 answer · posted 1y ago by brah‭ · last activity 1y ago by trichoplax‭

algorithm approximation numerical-analysis

60%

+1 −0

Why does the method of separating variables work?

0 answers · posted 1mo ago by The Amplitwist‭

partial-differential-equations separation-of-variables

75%

+4 −0

How to find perfect squares such that their base 9 representation is all 1s?

1 answer · posted 24h ago by CrSb0001‭ · last activity 6h ago by Lisanne‭

number-theory bases recreational-mathematics

25%

+0 −4

Picking 20 different numbers, in the same draw $\;$ vs. $\;$ picking 10 different numbers, in 2 different draws.

1 answer · posted 4mo ago by H7D‭ · last activity 4mo ago by Olin Lathrop‭

lottery

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