Mathematics Stack Exchange

0

votes

2

answers

12

views

Expected value of the sum of three different die

probability dice

answered 1 min ago Tomás Palamás 378

0

votes

0

answers

3

views

Looking for a solution for a constrained double sum $\sum_{a=1}^{N}\left(2\Bigl\lfloor{\frac{N}{a}}\Bigr\rfloor+1\right) \sum_{a=1}^{N} N$

summation constraints

asked 2 mins ago Lorenz H Menke 96

2

votes

1

answer

23

views

Enderton's sentential “tautological implication” subsumed by Enderton's first-order “logical implication”?

logic first-order-logic

answered 2 mins ago Derek Elkins 17.8k

0

votes

0

answers

3

views

Relation between primes and powers of two

number-theory prime-numbers modular-arithmetic exponentiation

asked 3 mins ago Razvan 168

0

votes

1

answer

15

views

Understanding Big O notation - discrete math?

discrete-mathematics

modified 3 mins ago J. W. Tanner 5,135

0

votes

0

answers

3

views

Why 17 mod 10 is equal to 9 , but 17^16 mod 10 is equal to 1

modular-arithmetic arithmetic exponentiation problem-solving

asked 3 mins ago Teuddy R 1

0

votes

1

answer

7

views

Why if $0 <|\lambda| < 1,$ then $(U^{-1} - \frac{1}{\lambda}I)$ invertible?

functional-analysis proof-explanation

answered 4 mins ago Severin Schraven 6,820

2

votes

2

answers

18

views

Show that a number $n$ is divisible by 6 if and only if it can be written as a sum of three distinct divisors.

elementary-number-theory natural-numbers

answered 4 mins ago Mark Fischler 34.5k

0

votes

1

answer

5

views

Determining Equation based on 2 Points and Horizontal Asymptote

graphing-functions

answered 4 mins ago Phil H 4,340

0

votes

0

answers

9

views

Prove that $\mu((0,\infty))=0$.

real-analysis measure-theory

asked 4 mins ago John Thompson 423

0

votes

0

answers

8

views

Ext sheaves as extension by zero of locally free sheaves.

algebraic-geometry complex-geometry sheaf-theory

modified 5 mins ago Alan Muniz 2,678

1

vote

0

answers

17

views

How is the replicator dynamic a gradient flow of the Fisher information metric?

differential-geometry gradient-flows fisher-information evolutionary-game-theory

modified 5 mins ago DrNesbit 66

-1

votes

0

answers

4

views

Prove that each set of 2-distant points on the plane has at most 5 elements.

combinatorics

asked 7 mins ago user9785 1

0

votes

0

answers

2

views

How many cubic graphs G are there such that |V(g)| = 10 and every cycle of G has length >= 5?

graph-theory coloring

asked 7 mins ago math 4ever 1

0

votes

2

answers

19

views

Integrals of products of sines and cosines with arbitrary periods

integration trigonometry fourier-series orthogonality

modified 10 mins ago lthompson 116

0

votes

0

answers

16

views

+50

Does this family of ODEs satisfy unicity? ( right hand side f(t,y) = g(t) y, with g in L1 )

ordinary-differential-equations

modified 11 mins ago pancho 556

1

vote

0

answers

15

views

Sum of two random variables uniformly distributed on circles

probability probability-theory

modified 12 mins ago Lisa 694

0

votes

0

answers

10

views

I have this matrix. It is a Gram matrix of some bilinear form on the R^n.

linear-algebra matrices bilinear-form

asked 12 mins ago Andrey Komisarov 79

2

votes

1

answer

31

views

Homeomorphism between upper closed hemisphere and disk.

general-topology proof-verification

modified 13 mins ago Paul Frost 13k

1

vote

1

answer

10

views

Clarification regarding the definition of a Tangent Space

manifolds tangent-spaces

answered 13 mins ago Trevor Gunn 15k

0

votes

0

answers

3

views

Distribution of arrival times of Poisson point processes

probability probability-distributions poisson-distribution

asked 14 mins ago David Stevens 39

8

votes

2

answers

146

views

Why intuitively do the quaternions satisfy the mixture of geometric and algebraic properties that they do?

matrices soft-question hypercomplex-numbers

modified 15 mins ago Ethan Bolker 46.6k

0

votes

0

answers

5

views

what is the apparent size of a 1' object that is 600' away?

geometry

modified 18 mins ago Andrew Li 4,186

1

vote

1

answer

17

views

How to calculate the energy of a partial differential equation that is not parabolic or hyperbolic

pde

answered 23 mins ago Yesfun Yeh 106

0

votes

0

answers

7

views

Angle between regression line and SD line when plots flipped

statistics regression standard-deviation linear-regression

asked 24 mins ago hbrown 1

0

votes

0

answers

11

views

How do non-principal ultrafilters 'know' the key elements of an infinite series when establishing the equivalence for hyperreals.

nonstandard-analysis

modified 24 mins ago East 62

1

vote

0

answers

15

views

Continuous functions, null sets and Lebesgue measurable sets

real-analysis measure-theory

asked 25 mins ago Pedro Santos 190

0

votes

0

answers

43

views

Proving Asymptotic stability in Lyapunov's theorem

real-analysis dynamical-systems nonlinear-system lyapunov-functions

modified 28 mins ago johnny09 709

0

votes

0

answers

8

views

Let $G$ be a group s.t. $|G|=pqr$ where p,q,r are primes that need not be distinct. Prove that G is soluble.

abstract-algebra group-theory

asked 32 mins ago Mathematical Mushroom 184

0

votes

0

answers

7

views

Find a function sarting with a Lebesgue-Stieltjes measure

measure-theory

modified 34 mins ago Bernard 124k

1

vote

0

answers

9

views

Is a stabilizer subgroup a symmetric subalgebra?

lie-algebras

modified 35 mins ago J. W. Tanner 5,135

2

votes

0

answers

24

views

A measure theoretic Lipschitz condition

functional-analysis measure-theory soft-question geometric-measure-theory

modified 35 mins ago Riku 155

0

votes

1

answer

10

views

if $x=\cos(2a)\cos(5a)cos(6a)$ and $y=\cos(a)\cos(3a)\cos(9a)$ then prove that : $64xy=-1$ , $a=\frac{π}{13}$

real-analysis calculus trigonometry pi

modified 36 mins ago Fãtįma Ens 19

1

vote

0

answers

27

views

Step in the proof of the continuity of the Gauss Gamma function

sequences-and-series complex-analysis continuity uniform-convergence gamma-function

modified 37 mins ago userr777 314

3

votes

1

answer

27

views

If $R$ is a right-Noetherian ring and the Jacobson radical satisfies the right Artin-Rees property, then $\bigcap^{\infty}_{n=1}\text{Jac}(R)^n = 0$

abstract-algebra proof-verification ring-theory noetherian

answered 39 mins ago egreg 186k

0

votes

1

answer

13

views

Determine interval of convergence for $\sum_{n=1}^{\infty} {n!(8x-1)^n}$

sequences-and-series power-series

answered 40 mins ago José Carlos Santos 177k

0

votes

1

answer

20

views

Tangent line of non-simple curves

differential-geometry curves

answered 40 mins ago Ted Shifrin 65.1k

0

votes

0

answers

3

views

Nonnegative matrix exercise by Minc

linear-algebra matrices nonnegative-matrices

asked 41 mins ago Alfdav 104

0

votes

0

answers

5

views

Separable equations and implicit differentiation and differential form.

ordinary-differential-equations

asked 41 mins ago Jwan622 2,409

0

votes

0

answers

6

views

Let C be a cycle of length 2k+1 where k>=1 is an integer.

graph-theory

asked 43 mins ago math 4ever 1

0

votes

1

answer

12

views

Finding the curve of intersection of a cylinder and cone

geometry multivariable-calculus

modified 43 mins ago Ted Shifrin 65.1k

-1

votes

1

answer

6

views

Markov Process question

markov-process

answered 44 mins ago Mark Fischler 34.5k

1

vote

1

answer

9

views

Legendre-Fenchel conjugate: $\dot x \in \operatorname{dom}(\Psi^), -\operatorname{D}\mathcal E(x) \in \partial \Psi^(\dot x)$

convex-analysis gradient-flows

answered 44 mins ago Tony S.F. 3,916

0

votes

0

answers

20

views

Studying the uniform convergence of $S_n(z) = 1+z^2 - \frac{1}{(1+z^2)^{n-1}} $

sequences-and-series complex-analysis

modified 44 mins ago StubbornAtom 6,624

1

vote

1

answer

25

views

Find a function satisfies an integrals

lebesgue-integral lebesgue-measure

modified 45 mins ago PhoemueX 27.7k

1

vote

0

answers

21

views

How to simplify this expression $0^xy^0 + 1^xy^1 + 2^xy^2 + 3^xy^3 +…+n^x*y^n$.

linear-algebra

modified 46 mins ago dngup 6

0

votes

0

answers

17

views

How to determine expected number of $n$ unif(0,1) random variables required to sum past 1.

probability stochastic-processes

modified 47 mins ago JimmyK4542 41.5k

0

votes

0

answers

10

views

Change of base matrix between displaced and rotated coordinate systems

linear-algebra matrices coordinate-systems change-of-basis

modified 48 mins ago Alex Vong 1,371

0

votes

0

answers

11

views

there exists a bipartite graph whose size $\geq \frac{m}{2}$

graph-theory

asked 48 mins ago Hunnam 117

0

votes

0

answers

3

views

How to solve $F(t) = a\sin{t} - 2 \int^1_0 F(u) \cos(t - u) du$

integration integral-equations

asked 49 mins ago user168282 29

0

votes

0

answers

6

views

For a given set $S$ , is it possible to find a well ordered set $T$ such that every $S$ indexed subset of $T$ has a strict upper bound?

set-theory

asked 51 mins ago user2628206 22

0

votes

1

answer

22

views

Heat equation with initial boundary problem

pde

answered 52 mins ago Alex R. 25.3k

2

votes

2

answers

21

views

Is it necessary that $f: G_1 \to G_2$ is an isomorphism, for $f:H\to H$ an automorphism with $G_1, G_2\le H$ of the same cardinality?

group-theory group-isomorphism

answered 55 mins ago Antoine Giard 962

1

vote

1

answer

14

views

Distance of centre of an ellipse touching both the positive X and Y axes from origin when the ellipse is being rotated

geometry conic-sections

answered 58 mins ago user376343 3,983

0

votes

2

answers

15

views

Volume of the pyramid - how to find the coordinates of 4 vertices?

geometry analytic-geometry volume

answered 58 mins ago Mark Fischler 34.5k

0

votes

0

answers

27

views

How to know what $q$ is when $p$ and $f(p)$ are known in $f(p) = qpq^{-1}$

geometry quaternions

modified 1 hour ago berylliumquestion 1

0

votes

0

answers

38

views

How to solve $\int^1_0 \frac{y(u)}{\sqrt t - u} {d}u = \sqrt t $

integration

modified 1 hour ago Clayton 19.7k

0

votes

1

answer

18

views

Show that $\int_{-N}^N|x|^pF(dx)\le\limsup\int_{-N}^N|x|^pF_n(dx)\lt\infty$

probability-theory weak-convergence

modified 1 hour ago dnqxt 812

-1

votes

0

answers

12

views

Prove that either $G$ has $K(t+1)$ as a minor or chromatic $(G) \leq t$

graph-theory

modified 1 hour ago angryavian 42.9k

2

votes

1

answer

39

views

About extracting a summable subsequence from a nonsummable sequence

sequences-and-series summability-theory

modified 1 hour ago Tony S.F. 3,916

0

votes

0

answers

4

views

Variance of cumulative incidence function

random-variables variance

asked 1 hour ago Watts 1

2

votes

1

answer

24

views

A new stopping time built from a stopping time

probability-theory martingales stopping-times

modified 1 hour ago saz 82.8k

3

votes

2

answers

25

views

Proof that every common divisor divides GCD (solve only by Bézout's identity)

number-theory elementary-number-theory proof-verification

answered 1 hour ago egreg 186k

8

votes

1

answer

79

views

can the product of four positive integers in A.P. be a square?

elementary-number-theory

answered 1 hour ago Adam Bailey 2,159

0

votes

0

answers

14

views

Meaning of absolute constant

complex-analysis number-theory definition analytic-number-theory dirichlet-series

asked 1 hour ago user366818 1,119

2

votes

0

answers

38

views

find the bmatrix $\det(x,1,0,0,\cdots)$

linear-algebra matrices determinant tridiagonal-matrices

modified 1 hour ago darij grinberg 11.6k

2

votes

1

answer

14

views

Ideals of subsets in $k[x_1,..,x_n]$

algebraic-geometry

answered 1 hour ago Kenny Wong 20k

1

vote

1

answer

20

views

Can anyone give me an example of an Euclidean Domain $D$ whose Euclidean Valuation at a point $a$: $v(a)$ is bigger than $\min \{v(ax) : x\in D\}$?

abstract-algebra ring-theory euclidean-domain

answered 1 hour ago MatheinBoulomenos 8,134

1

vote

0

answers

23

views

Understanding the Following Integral Notation

integration physics quantum-mechanics spherical-harmonics

asked 1 hour ago Kosta 532

0

votes

0

answers

15

views

Are there non-embedded tori in Lie groups?

lie-groups

asked 1 hour ago pizzaroll 400

1

vote

1

answer

28

views

Show that a functional has no extremal

calculus-of-variations functional-calculus

modified 1 hour ago Qmechanic 5,207

0

votes

0

answers

11

views

Determining Graph Automorphisms by Determining Ways of Permuting Edges

graph-theory symmetry graph-automorphism

modified 1 hour ago user193319 2,495

1

vote

0

answers

12

views

Advantage of using Hidden Markov Model over Markov Chain

markov-chains hidden-markov-models

asked 1 hour ago jhon_wick 303

0

votes

0

answers

23

views

Hausdorff Property for Preschemes in Mumford's Red Book

algebraic-geometry schemes

modified 1 hour ago KarlPeter 763

0

votes

0

answers

9

views

Computation of the push forward of vectors

manifolds vector-fields

asked 1 hour ago casimir 40

0

votes

0

answers

23

views

RSA - statements re $\phi(n)$, $\lambda(n)$ and $n$, given $n$ and $e=65537$

group-theory number-theory factoring cryptography

modified 1 hour ago unseen_rider 462

0

votes

0

answers

24

views

Regular polygons with equal height

geometry trigonometry polygons

modified 1 hour ago SacredGeometry 101

0

votes

0

answers

7

views

Estimating population size of endangered parrots

statistics statistical-inference descriptive-statistics

asked 1 hour ago Jack Haines 6

0

votes

0

answers

11

views

Best linear prediction as a projection in a Hilbert space $L^2$

statistics projection

asked 2 hours ago Fam 31

2

votes

1

answer

64

views

Inequality for a differentiable concave function on $[0,1]$

real-analysis

modified 2 hours ago zhw. 75.2k

0

votes

1

answer

26

views

Why is uniqueness a requirement for well-posed problems?

numerical-methods

answered 2 hours ago Robert Israel 332k

1

vote

0

answers

12

views

Show that $[\widetilde{X},\widetilde{Y}]^H=\widetilde{[X,Y]}$ and that $[\widetilde{X},W]$ is vertical if $W$ is vertical.

riemannian-geometry connections

asked 2 hours ago TheConjecture 6

0

votes

3

answers

39

views

The paradox of random occurrence the family problem

probability paradoxes

answered 2 hours ago Ned 2,103

0

votes

0

answers

6

views

Proof of equivalence of S-TSP solution with TSP solution (metric instances)

graph-theory optimization algorithms hamiltonian-path

asked 2 hours ago BraveDistribution 1

0

votes

0

answers

15

views

How to aggregate the normal distributions of two Kalman populations?

probability-theory statistics bayesian-network kalman-filter

modified 2 hours ago Pedro Carvalho 399

0

votes

0

answers

9

views

Poset and lattice

discrete-mathematics

asked 2 hours ago Arpit Gupta 1

6

votes

1

answer

134

views

+300

How do I prove that the second derivative of a function $f:M\to\mathbb{R}$ defined on a surface $M\subset\mathbb{R}^n$ is well defined?

real-analysis multivariable-calculus derivatives differential-geometry differential-topology

modified 2 hours ago MathOverview 8,692

2

votes

0

answers

31

views

+50

Conditionnal entropy : intuitive interpretation

information-theory entropy

modified 2 hours ago StarBucK 349

3

votes

2

answers

16

views

Showing a mapping is bijective if and only if a matrix is invertible

linear-algebra matrices multivariable-calculus functions derivatives

answered 2 hours ago Berci 62.1k

0

votes

0

answers

6

views

Epigraphical Cones, Fenchel Conjugates, and Duality

convex-analysis dual-cone

asked 2 hours ago Ariel Serranoni 63

0

votes

0

answers

3

views

Policy gradient base line function

calculus probability derivatives machine-learning

asked 2 hours ago AlphaBeta 23

2

votes

1

answer

27

views

ODE with discontinuous vector field

ordinary-differential-equations measure-theory numerical-methods vector-fields geometric-measure-theory

modified 2 hours ago Rodrigo de Azevedo 13.2k

3

votes

1

answer

33

views

Simple process in Itô calculus

probability-theory stochastic-processes stochastic-calculus brownian-motion stochastic-integrals

answered 2 hours ago Will 526

0

votes

1

answer

44

views

+150

Logistic growth model

mathematical-modeling

answered 3 hours ago Joaquin San 807

0

votes

0

answers

8

views

Existence of a particular complex atlas (and nested precompact sets)

general-topology

asked 3 hours ago SystematicDisintegration 279

3

votes

0

answers

23

views

How to show that two trigonometric polynomials of degree $n$ combined have at most $2n$ zeros?

real-analysis trigonometry polynomials roots

asked 4 hours ago Raito 703

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