Mathematics Stack Exchange

0

votes

1

answer

11

views

arctan of ratio of two normal variables is uniform

probability-distributions normal-distribution uniform-distribution

answered 3 mins ago Alessandro Cigna 1,383

-3

votes

0

answers

10

views

If $\alpha$ and $\beta$ are the roots of $x^2-4x+5=0$, find $(\alpha^3-4\alpha^2+6\alpha+2)(\beta^3-4\beta^2+6\beta+2)$

polynomials quadratics

modified 3 mins ago Blue 59.2k

0

votes

0

answers

5

views

Coordinates of the vectors of the canonical basis with respect to another basis.

linear-algebra vector-spaces

asked 5 mins ago mozzarino 27

0

votes

2

answers

15

views

Show that a martingale $\{X_n\}$ is bounded in $L^2$ if and only if $EX_n^2<\infty$ for each $n$ and $\sum_{n\ge1}E(X_{n+1}-X_n)^2<\infty$

probability probability-theory self-learning martingales

answered 1 min ago Kavi Rama Murthy 203k

1

vote

0

answers

12

views

What are the elements of $G_0(\Omega)$ and of $G_1(\Omega)$?

functional-analysis analysis derivatives solution-verification schwartz-space

modified 11 mins ago Guilherme de Loreno 812

0

votes

0

answers

4

views

Binomial conditional on Poisson

probability probability-theory conditional-probability poisson-distribution binomial-distribution

asked 11 mins ago linhares 101

2

votes

1

answer

40

views

Probability that $a$ and $b$ are in some subset of $\{0, \cdots, n-1\}$, where $a$ and $b$ are not independent?

probability

modified 13 mins ago Maximilian Janisch 8,943

6

votes

2

answers

1k

views

Every smooth cubic curve has a flex point

algebraic-geometry elliptic-curves

modified 15 mins ago amateur 27

6

votes

0

answers

25

views

General integral $\int_0^{\frac{\pi}{p}}\ln\tan x dx $

inequality definite-integrals special-functions closed-form

modified 16 mins ago Naren Naruto 1,267

0

votes

0

answers

5

views

How can I solve for the Jacobian matrix of a complementary log function?

logarithms exponential-function partial-derivative jacobian

modified 16 mins ago Sebastiano 2,086

0

votes

0

answers

16

views

How can I solve this nonlinear Partial differential equation?

partial-differential-equations

modified 18 mins ago Vivid Kraig 1,495

0

votes

0

answers

9

views

Determine level curve of a Multivariable Function

calculus multivariable-calculus

modified 19 mins ago Yan Zhuang 357

0

votes

1

answer

16

views

Is a directed graph different from a flow graph?

graph-theory directed-graphs

modified 20 mins ago Q.P. 155

1

vote

0

answers

14

views

Given an embedding $f$ on a compact, $\exists\eta>0$ such that every mapping $\eta$-close to $f$ is embedding on some smaller set.

complex-analysis differential-geometry reference-request

modified 21 mins ago Joe 10k

2

votes

1

answer

58

views

How to solve for PDE (Greens function) for mixed Neumann-Dirichlet boundary value problem?

boundary-value-problem greens-function

modified 21 mins ago Fei Cao 53

3

votes

1

answer

38

views

Is the product of two Cesaro convergent series Cesaro convergent?

real-analysis sequences-and-series convergence-divergence proof-writing cesaro-summable

modified 22 mins ago alphaomega 1,087

1

vote

0

answers

26

views

Is it mathematically possible to solve this problem?

linear-algebra

asked 23 mins ago Sarah 31

2

votes

1

answer

37

views

Help! Lyapunov proof for calculated torque control with friction term for robot

control-theory stability-theory lyapunov-functions robotics

modified 25 mins ago abc1455 346

1

vote

1

answer

37

views

Prime ideals of $\Bbb C[x, y]$

algebraic-geometry commutative-algebra

modified 25 mins ago Kenny Wong 22.1k

7

votes

1

answer

2k

views

Symmetrizing matrix properties

linear-algebra matrices

modified 28 mins ago Community♦ 1

1

vote

1

answer

37

views

How to solve this problem of Numerical Differentiation

numerical-methods

modified 29 mins ago Moo 7,368

0

votes

0

answers

31

views

I found a new theorem in geometry. Can anyone spot errors, or tell me how to get it published?

geometry trigonometry taylor-expansion

asked 30 mins ago Noah King 1

1

vote

0

answers

30

views

What kind of curvature?

differential-geometry riemannian-geometry semi-riemannian-geometry

modified 31 mins ago Jongar Jongar 33

0

votes

0

answers

8

views

Difference between two not necessarily identical uniform distributions

probability probability-theory probability-distributions uniform-distribution

asked 33 mins ago Learning Math 1,550

2

votes

1

answer

31

views

Trying to prove any relation between elements of a group can be derived from the relations in the presentation of the group

abstract-algebra group-theory group-presentation

answered 33 mins ago HallaSurvivor 6,225

1

vote

0

answers

7

views

For a given circle, prove that the lines of intersections by circles that pass through two given points converge at one point.

geometry euclidean-geometry circles geometric-construction

asked 34 mins ago Taxxi 1,226

0

votes

1

answer

14

views

An exercise regarding the computation of partial derivatives and applying the Chain Rule

solution-verification partial-derivative

modified 36 mins ago Ted Shifrin 81.1k

0

votes

1

answer

21

views

How to use general recursion to generate a set of words?

set-theory recursion

modified 37 mins ago Alexandru Dinu 302

-2

votes

0

answers

15

views

Hello, do you know how to calculate this work using integrals?

integration volume

asked 41 mins ago Andres Sandoval 1

0

votes

0

answers

7

views

Containment of Bruhat cells on flag variety

algebraic-geometry algebraic-groups

asked 41 mins ago Qixian Zhao 133

1

vote

1

answer

24

views

How does topological properties of sets (openness, closed, compactness) matter in practical algorithm design for optimization problems?

real-analysis numerical-methods convex-optimization numerical-optimization math-software

answered 45 mins ago Zim 1,699

1

vote

0

answers

14

views

Rational singularity of Spec, Proj and Spec of localization of a standard graded $2$-dimesional ring

algebraic-geometry commutative-algebra schemes derived-functors birational-geometry

modified 46 mins ago Louis 168

0

votes

2

answers

31

views

Is it always possible to find a decomposition of cubic graphs into paths with average length three, and why?

graph-theory

answered 47 mins ago Fábio Botler 1

1

vote

2

answers

25

views

Is there any visual representation on why (certain) trigonometric functions have infinite derivatives.

calculus derivatives trigonometry

answered 54 mins ago Doug M 51.2k

1

vote

0

answers

14

views

Example of $A \subseteq k[x,y]$, $\dim(A)=2$, $J$ non-maximal ideal of $k[x,y]$ and $J \cap A$ a maximal ideal of $A$

algebraic-geometry polynomials ring-theory commutative-algebra maximal-and-prime-ideals

modified 1 hour ago user237522 5,015

0

votes

0

answers

12

views

Find Greens function associated with quadratic form

partial-differential-equations greens-function poissons-equation

asked 1 hour ago PPR 1,009

5

votes

1

answer

88

views

Solving for positive reals: $abcd=1$, $a+b+c+d=28$, $ac+bc+cd+da+ac+bd=82/3$

algebra-precalculus inequality polynomials contest-math roots

modified 1 hour ago dezdichado 7,712

1

vote

1

answer

17

views

Is $(I \circ A - I \circ B)$ positive semi-definite if $A$, $B$ and $A - B$ are positive semi-definite?

linear-algebra hadamard-product

answered 1 hour ago s.harp 15k

1

vote

1

answer

38

views

How do we calculate the integral of measurable functions which are not Riemann integrable?

measure-theory definition lebesgue-integral measurable-functions

answered 1 hour ago zkutch 2,586

0

votes

0

answers

17

views

Mr. Rubio mixes a 75% sugar cinnamon-flavored solution with a 95% sugar cherry-flavored solution to make 20 gallons of a new product.

systems-of-equations

modified 1 hour ago Alexey Burdin 4,172

2

votes

0

answers

35

views

The diophantine equation $ m = x^2 + 7y^2 $

number-theory elementary-number-theory

modified 1 hour ago peter.petrov 7,851

0

votes

0

answers

6

views

Compressed Trie Run-time(s)

trees compression

asked 1 hour ago Sandy 21

0

votes

1

answer

31

views

On wreath product of finite $p$-groups

finite-groups representation-theory p-groups wreath-product

answered 1 hour ago David Craven 1,273

0

votes

1

answer

16

views

Show that the induced mapping $\hat{\phi}: X/\sim \to Y/\approx$ is continuous (Marsden, Ratiu, Abraham)

general-topology solution-verification

answered 1 hour ago Paul Frost 30.5k

0

votes

0

answers

15

views

Is a convex set of permutation matrices $n\times n$ ($\mathbb{P}_{n}\cap \mathbb{C}$) a singleton?

matrices elementary-set-theory convex-analysis permutation-matrices

modified 1 hour ago Joey Cho 101

1

vote

1

answer

11

views

Find $a+b+c$ given that segment $EC$ in the diagram can be written in the form $a(\sqrt{b}+\sqrt{c})$

geometry

answered 1 hour ago Quanto 39.6k

0

votes

1

answer

33

views

What is the condition for two extreme points?

calculus

modified 1 hour ago Sebastiano 2,086

0

votes

1

answer

25

views

Let $x=\begin{bmatrix}3\cr4\end{bmatrix}$ and $A=\begin{bmatrix}0&x^T\cr x&0\end{bmatrix}$ is A diagonizable?

linear-algebra matrices problem-solving

answered 1 hour ago Robert Israel 383k

2

votes

1

answer

27

views

Convergence of $e^{itH}$ as a sum for $H$ and unbounded operator

operator-theory spectral-theory quantum-mechanics

modified 1 hour ago Stephen Montgomery-Smith 19.6k

0

votes

0

answers

11

views

Simple Linear Regression help in this example!

probability probability-theory statistics random-variables linear-regression

asked 1 hour ago Antonio Cepeda Rodriguez 1

-1

votes

0

answers

19

views

Group of homomorphisms of ideals, how to characterize it?

abstract-algebra commutative-algebra

modified 1 hour ago Chickenmancer 3,622

2

votes

0

answers

41

views

Are we guaranteed a Lie group by taking the algebraic closure of finitely many one-parameter groups acting (each periodically) on a Euclidean space?

manifolds lie-groups lie-algebras

modified 1 hour ago avs 5,369

6

votes

1

answer

228

views

Does minimal submanifolds minimize area locally?

differential-geometry riemannian-geometry minimal-surfaces calibrated-geometry

modified 1 hour ago Arctic Char 2,342

0

votes

0

answers

18

views

The number of types on a set is equal to $\binom{n + m - 1}{m - 1}$?

probability combinatorics information-theory

asked 1 hour ago ironX 1,834

0

votes

0

answers

10

views

classification of optimization problem

optimization

asked 1 hour ago Bing 1

0

votes

1

answer

19

views

Show that $\sup_{k \geq 1 }\inf_{n \geq k} a_n = \inf_{k \geq 1} \sup_{n \geq k} a_n$ for an alternating sequence

sequences-and-series supremum-and-infimum

answered 1 hour ago zkutch 2,586

3

votes

1

answer

63

views

A doubt from book Spinors and Calibrations

lie-groups riemannian-geometry homogeneous-spaces spin-geometry octonions

modified 1 hour ago Arctic Char 2,342

0

votes

0

answers

12

views

Solution to a System of Equations for Conformally Transformed Metric

ordinary-differential-equations differential-geometry

asked 1 hour ago Tom 744

1

vote

0

answers

14

views

Extending an operator from $C([0,1])$ to $L^2([0,1])$

functional-analysis operator-theory lp-spaces

asked 1 hour ago AspiringMathematician 2,058

1

vote

0

answers

7

views

Floating Point Rounding of 2 multiplied single precision numbers

computer-science floating-point rounding-error computer-arithmetic

asked 1 hour ago R Mcgowan 13

4

votes

0

answers

23

views

Why does MINRES converge in 3 iterations on matrices of specific form?

linear-algebra numerical-linear-algebra sparse-matrices

modified 2 hours ago Jens Renders 3,709

0

votes

0

answers

19

views

To 3D world point with height instead of depth estimate

linear-algebra geometry

modified 2 hours ago Arctic Char 2,342

0

votes

0

answers

13

views

What is the derivation for the targets used in Platt Scaling?

probability machine-learning maximum-likelihood

modified 2 hours ago Arctic Char 2,342

1

vote

0

answers

21

views

camera calibration problem - computer vision

computer-vision robotics

modified 2 hours ago Arctic Char 2,342

0

votes

0

answers

5

views

What is the difference between shape and width of a Gaussian pulse?

geometry

asked 2 hours ago Paddy 166

2

votes

4

answers

44

views

What should n be equal to, so that the number is completely divisible by 19

elementary-number-theory modular-arithmetic exponential-function

answered 2 hours ago Barry Cipra 69k

0

votes

0

answers

21

views

Proving that $g_nf_n$ converges to $0$ in measure on $[0,1]$

real-analysis measure-theory

modified 2 hours ago Arctic Char 2,342

2

votes

0

answers

15

views

Every h-cobordism embeds into $M \times I$?

algebraic-topology manifolds geometric-topology

asked 2 hours ago Connor Malin 5,545

7

votes

1

answer

129

views

Stability analysis of the dynamical system $\ddot{x}+b\dot{x}+K x-\|\dot{x}\| \frac{x-x_i}{\|x-x_i\|^2}=0$ .

ordinary-differential-equations dynamical-systems control-theory stability-in-odes non-linear-dynamics

modified 2 hours ago abc1455 346

2

votes

1

answer

52

views

Stalks of Higher direct images of structure sheaf at smooth points

algebraic-geometry commutative-algebra schemes sheaf-cohomology derived-functors

modified 2 hours ago KReiser 28k

5

votes

0

answers

104

views

+50

Sum $\sum_{(k_1, k_2, k_3): k_1+k_2+k_3=K, \,\, n_1+n_2+n_3=N}k_1^{n_1}\times k_2^{n_2} \times k_3^{n_3}$

combinatorics number-theory elementary-number-theory bernoulli-numbers bernoulli-polynomials

modified 2 hours ago user4164 261

0

votes

3

answers

93

views

Geometry with Medians

geometry

modified 2 hours ago Community♦ 1

2

votes

1

answer

66

views

How to show that $2\sum_{j=1}^{N}\cot(\frac{\pi j}{2N+1})$ is related to $(\frac{4 \text{N}+2}{\pi}) (H_{\text{N}}+\log (\frac{2}{\pi }))$?

integration sequences-and-series limits summation trigonometric-series

answered 2 hours ago skbmoore 3,758

0

votes

0

answers

7

views

Generalizations of PERT diagrams

optimization operations-research

asked 2 hours ago User 21

1

vote

0

answers

13

views

A detail in proving that a sequence of uniformly integrable random variables converges weakly.

analysis probability-theory random-variables lp-spaces weak-convergence

modified 2 hours ago Paralyzed_by_Time 437

2

votes

1

answer

30

views

CFL grammer questions

automata context-free-grammar

answered 2 hours ago Brian M. Scott 508k

1

vote

0

answers

18

views

Equivalent of a set defined an inequality

abstract-algebra

modified 2 hours ago Mike 177

0

votes

0

answers

19

views

Probability of a random sample not completely covering any subset within a collection

probability combinatorics

modified 2 hours ago StubbornAtom 11.6k

0

votes

0

answers

18

views

Theory behind t-SNE

statistics machine-learning

modified 3 hours ago user13827069 11

0

votes

0

answers

12

views

Welch-Satterthwaite

probability probability-distributions gamma-distribution

modified 3 hours ago StubbornAtom 11.6k

3

votes

0

answers

21

views

Proving that $\sup_{B_R} |u| \leq \frac{R^2}{2n} \sup_{B_R} |f|$.

partial-differential-equations maximum-principle

asked 3 hours ago shedsaw 63

1

vote

0

answers

26

views

Measure of a circle is invariant under rotation

measure-theory solution-verification lebesgue-measure circles

modified 3 hours ago Alphie 615

0

votes

0

answers

12

views

Existence of a 3D Riemannian manifold with neck pinch singularity and Mobius loop

differential-geometry riemannian-geometry quantum-mechanics general-relativity

asked 3 hours ago Adam Herbst 1

1

vote

0

answers

21

views

If $X_n\thicksim\text{Unif}\left\{\frac{1}{n},\frac{2}{n},\dots,\frac{n-1}{n},1\right\}$ then $X_n\overset{d}\to Z$ where $Z\thicksim\text{Unif}[0,1]$

probability-theory probability-distributions solution-verification

asked 3 hours ago Stackman 3,040

2

votes

0

answers

16

views

Homomorphic Image of ideal in Lie algebras

abstract-algebra lie-algebras group-homomorphism maximal-and-prime-ideals vector-space-isomorphism

asked 3 hours ago Hamada Al 790

1

vote

1

answer

37

views

Ideals in a UFD

abstract-algebra

modified 3 hours ago cansomeonehelpmeout 8,816

3

votes

2

answers

170

views

Evaluating $\prod^{100}_{k=1}\left[1+2\cos \frac{2\pi \cdot 3^k}{3^{100}+1}\right]$

trigonometry

modified 3 hours ago ABCD 196

6

votes

1

answer

1k

views

Constructibility of the 17-gon

geometry field-theory euclidean-geometry polygons

answered 3 hours ago Nemo 1,312

4

votes

0

answers

24

views

Example of a flow that does not preserve volume measure (autonomous ode)

ordinary-differential-equations measure-theory dynamical-systems

asked 3 hours ago Raquel Magalhães 331

1

vote

0

answers

6

views

Optimal location of nucleation sites for voronoi partition of a square

optimization convex-optimization computational-geometry

asked 3 hours ago Mouli 71

0

votes

0

answers

22

views

Let $f:A\subset \mathbb{R}^{n+k}\rightarrow \mathbb{R}^n$ of class $C^1$

real-analysis analysis derivatives implicit-function-theorem

modified 3 hours ago SMM 4,122

3

votes

0

answers

55

views

Conceptually, what is the meaning / the idea of conjugacy?

linear-algebra general-topology group-theory algebraic-topology intuition

asked 3 hours ago R. Srivastava 31

2

votes

0

answers

14

views

Fubini Study Metric comes from Riemannian Submersion

differential-geometry complex-geometry kahler-manifolds

asked 4 hours ago Silas 63

4

votes

0

answers

45

views

Prove that no integer $w$ exists such that the splitting field of $x^4+x^3+x^2+x+1+w$ is that of $x^4+x^3+x^2+x+1$.

number-theory polynomials field-theory splitting-field cyclotomic-fields

modified 4 hours ago Batominovski 46.1k

2

votes

0

answers

62

views

Irreducibility of $X\times_k\overline{k}$ (Hartshorne 3.15 (a))

algebraic-geometry sheaf-theory schemes affine-schemes

modified 4 hours ago rmdmc89 6,611

0

votes

1

answer

11

views

Isolate a variable within a round function

algebra-precalculus

answered 4 hours ago Tavish 6,207

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