Mathematics Stack Exchange

1

vote

2

answers

8

views

ordering 8 people around table if 3 people do not want to sit next to each other

combinatorics

answered 1 min ago Barry Cipra 70.1k

1

vote

1

answer

32

views

$H^1$-conforming approximation for elliptic PDE with discontinuous coefficient?

sobolev-spaces regularity-theory-of-pdes finite-element-method elliptic-equations

modified 1 min ago epiliam 1,187

1

vote

0

answers

13

views

Solving the equation $\sqrt{x+2} + \sqrt{4x+1} = 5$.

geometry algebra-precalculus

modified 1 min ago Blue 59.9k

1

vote

1

answer

22

views

Solving for p binomcdf(n,p,k)=x

probability numerical-methods

answered 2 mins ago Henry 119k

0

votes

0

answers

4

views

Guessing colored hats without repetition

combinatorics latin-square

asked 3 mins ago Nikhil Sahoo 651

0

votes

0

answers

8

views

Why does the standard deviation square numbers?

average standard-deviation

modified 6 secs ago Joe DiNottra 101

0

votes

1

answer

20

views

Compare the growth rate of $f(x)$ and $g(x)$ and show how much quicker the quicker of the two grow

hyperoperation

modified 8 mins ago Aprontic Alchemist 1

0

votes

2

answers

1k

views

Convergent iff lim-inf=lim-sup

real-analysis

modified 10 mins ago Community♦ 1

0

votes

0

answers

5

views

Painting a different board in a particular way

combinatorics

asked 17 mins ago Thales Athanasio 1

-1

votes

0

answers

18

views

$f : R \to (0, \infty)$ ise a monotone decreasing function. Suppose $x_1 = 1$, $x_{n+1} = x_n + f(x_n)$ for $x \in N$. Show $x_n \to \infty.$

real-analysis sequences-and-series analysis

modified 19 mins ago amWhy 198k

0

votes

0

answers

11

views

Finding slope of lines using tangent and angles between them

geometry trigonometry

asked 20 mins ago raynea 171

0

votes

0

answers

53

views

How to evaluate $\int_0^1 \int_0^1 \frac{1}{1-u^2+v^2}dudv$?

multivariable-calculus

modified 27 mins ago Integrand 6,504

0

votes

0

answers

5

views

Composite canonical transformation using Lie operators

classical-mechanics perturbation-theory lie-derivative hamilton-equations canonical-transformation

asked 33 mins ago user135626 890

2

votes

3

answers

48

views

Why proofs are not written in collections of logic symbols but are instead written in sentences?

real-analysis multivariable-calculus proof-writing propositional-calculus step-function

answered 34 mins ago crystal_math 1,286

2

votes

3

answers

20

views

Delta method and asymptotic variance

probability sequences-and-series probability-theory convergence-divergence weak-convergence

answered 41 mins ago kimchi lover 19.9k

0

votes

0

answers

7

views

Giving an $\epsilon$ of room: analysis of k-NN algorithm

probability solution-verification

asked 44 mins ago MONODA43 468

0

votes

0

answers

9

views

Convergence of AR(1) process

convergence-divergence stochastic-processes stationary-processes

asked 45 mins ago Doris_P 184

0

votes

0

answers

12

views

Prove $A_4$ acts on the set of edges of the tetrahedron T and find the stabilizer of $A_{4_{(1,2)}}$

abstract-algebra group-theory

asked 46 mins ago Hristmar 149

0

votes

1

answer

12

views

Solve for down payment and closing costs, given savings, home price, and closing costs percentage

algebra-precalculus systems-of-equations

answered 47 mins ago rogerl 20.3k

0

votes

1

answer

13

views

Finding positive semi-definite counterexamples for self-adjoint bounded operators on a Hilbert Space.

matrices operator-theory hilbert-spaces positive-semidefinite self-adjoint-operators

answered 49 mins ago PStheman 456

0

votes

1

answer

20

views

Probability of rolling same number at least twice on Yahtzee

combinatorics

modified 53 mins ago shortmanikos 513

0

votes

0

answers

8

views

Conditional distribution of normal rv problem

probability normal-distribution conditional-probability

asked 56 mins ago Xiaohuolong 161

4

votes

3

answers

59

views

Does the inequality $ \sqrt{a+b}\geq \sqrt{a/2}+\sqrt{b/2}$ have a name?

real-analysis reference-request

modified 56 mins ago James A 1,662

0

votes

0

answers

4

views

Variance of a sum of weighed random variables with standard normal distribution

probability probability-theory probability-distributions normal-distribution probability-limit-theorems

asked 56 mins ago Juanma Eloy 1,157

0

votes

0

answers

13

views

Finiteness requirement/non-requirement in Series results

sequences-and-series

modified 57 mins ago Aiden Chow 1,078

0

votes

0

answers

21

views

Area under a curve by using a different method

curves

modified 57 mins ago C Squared 945

0

votes

1

answer

15

views

The kernel of a killing form is solvable.

solution-verification lie-groups lie-algebras

answered 1 hour ago JCAA 7,621

0

votes

0

answers

21

views

canonical form near a regular point

differential-geometry manifolds smooth-manifolds

modified 1 hour ago yi_li 657

0

votes

0

answers

4

views

Question about solving recurrence relation with constant in T(n) complexity

recurrence-relations computational-complexity

asked 1 hour ago zaynxalic 1

1

vote

0

answers

21

views

Is it true that $\text{If Pr$(\alpha)=1$, then $\alpha\equiv\top$}$

probability logic

modified 1 hour ago user_795606 97

2

votes

1

answer

20

views

for $y''+p(x)y'+q(x)=0$, $-\frac{W'(u',v')(x)}{W(u,v)(x)}=p(x)$ and $q(x)=\frac{W(u',v')(x)}{W(u,v)(x)}$

ordinary-differential-equations wronskian

modified 1 hour ago Robert Lewis 61.9k

0

votes

0

answers

10

views

$(vz-wy,wx-uz,uy-vx)$ is a prime ideal

polynomials commutative-algebra maximal-and-prime-ideals

asked 1 hour ago T C 2,113

0

votes

2

answers

845

views

Triangle $ABC$ is isosceles with $AB=AC$, and $D$ is the midpoint of $AB$. If $\angle{BCD}=\angle{BAC}=θ$, then $\cos θ$ equals…?

geometry trigonometry

modified 1 hour ago Community♦ 1

5

votes

1

answer

545

views

+200

Inclusion/exclusion, at least and exactly arrangements?

combinatorics discrete-mathematics combinations inclusion-exclusion

modified 1 hour ago FtyRain 1,671

2

votes

0

answers

82

views

Why limit map induces isomorphisms of homotopy groups of all dimensions?

general-topology reference-request algebraic-topology differential-topology

modified 1 hour ago Si Kucing 5,059

0

votes

0

answers

9

views

Understanding bandwidth and density in a graph

statistics machine-learning density-function

asked 1 hour ago stats555 1

1

vote

1

answer

48

views

driving car on a sphere questions

geometry differential-geometry dynamical-systems analytic-geometry chaos-theory

answered 1 hour ago Lubin 52.8k

0

votes

0

answers

18

views

Spectrum of an operator on $\ell^2$

sequences-and-series functional-analysis operator-theory hilbert-spaces spectral-theory

modified 1 hour ago Conifold 9,689

0

votes

1

answer

19

views

Why is it not true that if $\Phi \models \exists x \phi$ then there is a term $t$ with $\Phi \models \phi \frac{t}{x}$?

logic computer-science model-theory programming

answered 1 hour ago Noah Schweber 173k

0

votes

1

answer

29

views

Help with moment generating function

probability generating-functions poisson-distribution moment-generating-functions

answered 1 hour ago Daniel S. 691

0

votes

0

answers

47

views

Continuous, Smooth Function With Certain Requirements

smooth-functions

modified 1 hour ago DUO 83

0

votes

0

answers

10

views

Conditions for Nonempty Intersection of Polynomial Surfaces

geometry differential-geometry polynomials systems-of-equations

asked 1 hour ago Romain S 2,496

3

votes

1

answer

115

views

An inequality involving positive real numbers

inequality logarithms

modified 1 hour ago JCAA 7,621

0

votes

0

answers

27

views

Why a structure sheaf is a vector bundle?

differential-geometry algebraic-geometry

asked 1 hour ago Camford Oxbridge 199

0

votes

0

answers

26

views

Operator norm of a Hilbert-Schmidt Kernel

operator-theory norm

modified 1 hour ago Rishabh Jain 471

1

vote

1

answer

21

views

Absolute Value - Area of a Bounded Region

geometry algebra-precalculus area absolute-value

modified 1 hour ago J. W. Tanner 43.8k

-1

votes

1

answer

27

views

How many numbers of $6$ digit, using $1,2,4,5,7$ and $8$ are multiples of a $6$ Digit numbers, using $1,2,4,5,7$ and $8$?

combinatorics number-theory divisibility

modified 1 hour ago Robert Israel 387k

3

votes

1

answer

35

views

How to universalize $\text{Prov}(\ulcorner y < K(x)\urcorner) \to y < K(x)$ in a paper of Kikuchi

logic peano-axioms incompleteness kolmogorov-complexity

answered 2 hours ago Noah Schweber 173k

0

votes

0

answers

31

views

How can I enumerate the transformation rules on lists of lists?

algorithms pattern-matching

modified 2 hours ago zooby 3,347

3

votes

1

answer

25

views

Quasi Injective Ring equivalence.

modules direct-sum injective-module

answered 2 hours ago rschwieb 126k

1

vote

0

answers

17

views

Covariance inequality with Lipschitz functions

probability-theory

modified 2 hours ago Robert W. 652

0

votes

0

answers

22

views

Show that || . || is a norm on E and write the associated distance function corresponding to it.

polynomials vectors

modified 2 hours ago Oliver Diaz 9,697

0

votes

3

answers

106

views

Solving Linear Algebra Problem from Berkeley Qual Spring 1990 Using Calculus

calculus linear-algebra eigenvalues-eigenvectors

modified 2 hours ago user8675309 2,962

0

votes

1

answer

20

views

Tensor Calculus Notation

vector-analysis tensors index-notation

answered 2 hours ago peek-a-boo 15.6k

2

votes

3

answers

91

views

$f$ is 1-periodic prove $\lim_{n \to \infty} \int_{0}^{1} \sin^2(πx)f(nx)\,dx = \frac{1}{2} \int_{0}^{1} f(x)\,dx$

real-analysis calculus integration functions riemann-sum

modified 2 hours ago Oliver Diaz 9,697

0

votes

0

answers

29

views

Derivative of vector and matrix product

derivatives vectors matrix-calculus

modified 2 hours ago Pedro Ignacio Martinez Bruera 45

1

vote

1

answer

36

views

Stuck on this definite integration problem

calculus integration definite-integrals

modified 2 hours ago Ty. 4,336

2

votes

2

answers

63

views

Prove $\sqrt{a} \cos^2(\theta) + \sqrt{b} \sin^2(\theta) < \sqrt{c}$ if $a\cos^2(\theta) + b \sin^2(\theta) < c$

calculus inequality convex-analysis recreational-mathematics problem-solving

modified 2 hours ago Tortar 1,074

0

votes

1

answer

36

views

Epsilon delta proof, choosing inequality side

epsilon-delta

modified 2 hours ago azifmedrano 10.3k

0

votes

1

answer

17

views

Compute the variance in a result derived from a unit quaternion, when the quaternion variance-covariance matrix is known.

statistics variance covariance kalman-filter

answered 2 hours ago EBlake 133

0

votes

1

answer

30

views

Do primitive roots mod m always satisfy $\gcd(r^t,m)=1$?

elementary-number-theory totient-function primitive-roots

modified 2 hours ago Anna Naden 178

0

votes

0

answers

23

views

What's the cross ratio of 4 planes?

projective-geometry

modified 3 hours ago Aiden Chow 1,078

3

votes

1

answer

23

views

Any idea to prove that $\coth (x)-(1-y) \coth [x (1-y)]<\frac{4 x}{1-x^4}$?

inequality alternative-proof

answered 3 hours ago Calum Gilhooley 8,672

0

votes

0

answers

29

views

Completion of a Number Field at a Infinite prime

algebraic-number-theory

modified 3 hours ago math 179

0

votes

0

answers

13

views

Is there a nice relationship between $\dot{B}^{-1}_{p,1}$ and $\dot{B}^{0}_{p,1}$?

real-analysis functional-analysis norm lp-spaces besov-space

asked 3 hours ago David Hughes 498

0

votes

0

answers

22

views

Find equivalence classes and quotient set of $(x,y)R(w,z)\iff2(x-w)=z-y$

discrete-mathematics equivalence-relations quotient-set

asked 3 hours ago manooooh 1,985

1

vote

1

answer

22

views

Is every subspace of an incomplete inner product space closed?

functional-analysis hilbert-spaces inner-product-space

answered 3 hours ago Sebastian Spindler 249

1

vote

1

answer

20

views

Parallel lines thru Gergonne point produce intouch bisection

geometry

modified 3 hours ago peter.petrov 8,219

2

votes

0

answers

26

views

types which behave like sets

set-theory type-theory homotopy-type-theory

asked 3 hours ago push33n 103

0

votes

0

answers

9

views

How to update a distribution by using joint distribution of its function values?

probability-distributions bayesian estimation

modified 3 hours ago Mohsen Shahriari 3,755

0

votes

0

answers

10

views

Derivation of the Chebyshev distance from the Minkowski distance

data-mining

modified 3 hours ago Aiden Chow 1,078

0

votes

0

answers

10

views

Functional equation of Dirichlet's Beta function

special-functions

modified 3 hours ago Aiden Chow 1,078

0

votes

0

answers

19

views

Area question relating an intersection of a sphere with a cylinder.

geometry differential-geometry analytic-geometry diophantine-equations closed-form

asked 3 hours ago mick 12k

0

votes

0

answers

18

views

Closed (or not) but incomplete subspace of an incomplete inner product space

functional-analysis hilbert-spaces inner-product-space

modified 3 hours ago Physer 11

0

votes

1

answer

11

views

A type of Hölder function

real-analysis sobolev-spaces holder-spaces

answered 3 hours ago LL 3.14 3,586

1

vote

0

answers

11

views

Understanding the concept of $P(u/v)$ in the context of First Order Logic.

logic first-order-logic predicate-logic quantifiers

asked 3 hours ago F. Zer 1,650

0

votes

0

answers

23

views

Quaternions — Generalization of Taylor Series Polynomials to Higher Dimensional Numbers

sequences-and-series convergence-divergence taylor-expansion quaternions

asked 3 hours ago Raiyan Chowdhury 106

0

votes

0

answers

19

views

Nonlinear functional variational calculus

functional-equations calculus-of-variations

modified 3 hours ago F. Conrad 1,532

0

votes

0

answers

16

views

If $p,q \in B(\mathcal{H})$ are projections and $q\mathcal{H} \subset p\mathcal{H}$, show that $p\mathcal{H} = q\mathcal{H} \oplus (p-q)\mathcal{H}$.

operator-theory hilbert-spaces projection

asked 3 hours ago metricforbees 93

2

votes

1

answer

32

views

Proving that, if $\Vert f\Vert_{H^1}^2-\Vert g\Vert_{H^1}^2\to0$ and $\big\vert F(f)-F(g)\big\vert\to0$, then $\Vert f-g\Vert_{H^1}\to0$

partial-differential-equations sobolev-spaces calculus-of-variations

answered 3 hours ago Michał Miśkiewicz 3,123

1

vote

1

answer

17

views

About transcendence degree of an affine $K$-domain

commutative-algebra transcendence-degree

modified 3 hours ago Qiaochu Yuan 311k

0

votes

0

answers

23

views

Inner product of polynomials

algebraic-geometry polynomials commutative-algebra homology-cohomology

modified 3 hours ago Bernard 154k

0

votes

0

answers

18

views

The initial set is not a separator

category-theory

asked 4 hours ago usercolonname 1

1

vote

0

answers

26

views

How to calculate this binomial sum?

calculus sequences-and-series summation binomial-coefficients factorial

asked 4 hours ago Alexstudent 21

1

vote

2

answers

795

views

The base of a triangular prism is $ABC$. $A'B'C'$ is an equilateral triangle with lengths $a$…

geometry

modified 4 hours ago Community♦ 1

1

vote

0

answers

25

views

Hartshorne exercise II.4.5(c)

algebraic-geometry commutative-algebra

asked 4 hours ago Xin 77

4

votes

2

answers

67

views

Proving that a Gaussian integer $a+bi$ with $a,b\neq0$ is composite in $\mathbb{Z}[i]$ if its norm $a^2+b^2$ is composite in $\mathbb{N}$?

elementary-number-theory complex-numbers prime-numbers gaussian-integers

answered 4 hours ago Klaas van Aarsen 5,277

12

votes

1

answer

458

views

Analytic continuation of $\Phi(s)=\sum_{n \ge 1} e^{-n^s}$

complex-analysis reference-request soft-question riemann-zeta analytic-continuation

modified 4 hours ago metamorphy 18.6k

0

votes

0

answers

13

views

Learning to use the law of total probability

probability discrete-mathematics solution-verification

asked 4 hours ago user820555 1

6

votes

0

answers

177

views

+50

Proving Tonelli's Theorem for $n$ Factors

real-analysis measure-theory lebesgue-integral measurable-functions fubini-tonelli-theorems

modified 4 hours ago Alphie 779

0

votes

0

answers

11

views

Show that $T_a bb^T T_a=T_a^2+(a^Ta)bb^T$

linear-algebra

asked 4 hours ago ANZGC FlyingFalcon 101

3

votes

0

answers

49

views

Bolyai's parallel angle formula？

geometry surfaces hyperbolic-geometry noneuclidean-geometry

modified 4 hours ago Narasimham 28.9k

0

votes

0

answers

24

views

Equivalence relation in a category

category-theory

asked 4 hours ago Alec Rhea 1,285

1

vote

0

answers

20

views

Ring of invariant of finite groups and its subgroups

invariant-theory

modified 4 hours ago Nguyen Dang Son 70

-1

votes

0

answers

20

views

What website is goood for finding a value of $x$ for any value of $n$?

mixing-variables

modified 5 hours ago Aiden Chow 1,078

0

votes

0

answers

14

views

Fourier cosine series for a function on interval $[a,b]$

fourier-analysis fourier-series book-recommendation

asked 5 hours ago Math122 25

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