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3

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Prove that $\int\sum k\chi_{f^-1}<\infty$

measure-theory lebesgue-integral lebesgue-measure measurable-functions measurable-sets

asked 1 min ago Alejandro Bergasa Alonso 400

0

votes

0

answers

7

views

Computation of the integral $\int_0^{\infty} \frac{x^2}{(a^2-x^2)^2-x^2b^2}dx$

calculus integration definite-integrals

modified 2 mins ago Sumanta 3,667

0

votes

0

answers

4

views

Consider the group G = {0, 1, 2, 3} with binary operation x ∗ y = x + y(mod4). What is the identity element? and find the inverse of each element?

discrete-mathematics

asked 2 mins ago FSLD FSLD 1

0

votes

1

answer

15

views

Block matrix determinant property(sum)

matrices determinant block-matrices

modified 3 mins ago Rodrigo de Azevedo 15.2k

4

votes

2

answers

817

views

Rotman Introduction to Algebraic Topology Question 0.5

algebraic-topology

answered 3 mins ago Herlin 1

0

votes

1

answer

13

views

Accuracy of low rank approximation

matrices optimization matrix-decomposition matrix-rank

modified 3 mins ago Rodrigo de Azevedo 15.2k

1

vote

1

answer

11

views

Convert the given Boolean function into its $NOR$ Normal Form.

functions discrete-mathematics logic boolean-algebra

answered 4 mins ago Taroccoesbrocco 10.3k

0

votes

0

answers

11

views

Help for a proof with orthogonal unit vectors

linear-algebra matrices vector-spaces eigenvalues-eigenvectors proof-explanation

asked 5 mins ago DanteAligante 1

0

votes

0

answers

10

views

On the use of Weierstrass' M-test for uniform convergence of series including unbounded terms

real-analysis analysis

asked 6 mins ago serenus 689

0

votes

0

answers

6

views

Condition number of normalized matrices

matrices condition-number

modified 6 mins ago Rodrigo de Azevedo 15.2k

0

votes

0

answers

8

views

Single-valued enumeration of all c.e. sets

computability

modified 7 mins ago T uS 1

0

votes

1

answer

5

views

Differential Equations

derivatives

8 mins ago Naruto 1

0

votes

0

answers

7

views

How do you solve the differential equation dvx/dt = Cvy where vx and vy are the x and y component of velocity and C is a constant

calculus

asked 8 mins ago zopxm 11

0

votes

1

answer

16

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Inverting symmetric matrix

matrices inverse symmetric-matrices

answered 9 mins ago user1551 95k

1

vote

2

answers

19

views

Covariance of $X$ and $Y^2$, when $X,Y$ follow $N(0,1)$

probability

answered 9 mins ago tommik 579

0

votes

0

answers

2

views

Limit involving the regularized incomplete beta function

real-analysis limits probability-distributions

asked 9 mins ago Vuk 163

1

vote

0

answers

23

views

Given the point $T$ and the line $p$, find the distance between their orthogonal projections onto the plane $\pi$.

geometry vectors analytic-geometry solution-verification

modified 11 mins ago Cheesecake 4,452

0

votes

0

answers

9

views

How would one go about Laplace Transforming $max(0, sin(t))$?

complex-analysis laplace-transform

asked 11 mins ago Vladimir Vojnic Hajduk 35

0

votes

0

answers

4

views

Equivalence in strong convergence of operators

operator-theory banach-spaces

asked 11 mins ago Something 1,767

0

votes

0

answers

11

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About differential equations

derivatives

modified 12 mins ago Bernard 148k

0

votes

0

answers

5

views

Pairing probability (high school maths problem)

probability

asked 12 mins ago BooScout 169

0

votes

1

answer

14

views

What is wrong with my answer to the question below?

volume

answered 12 mins ago Harish Chandra Rajpoot 32.7k

0

votes

0

answers

10

views

The sup of square of root P which P is a constant

real-analysis analysis

modified 13 mins ago Reza 101

0

votes

2

answers

34

views

Compute a $n\times n$ determinant

matrices determinant

answered 14 mins ago Rodrigo de Azevedo 15.2k

0

votes

0

answers

2

views

Calculate percentage based on specific 0% and 100% in any numeric range

percentages

asked 16 mins ago SharpShade 101

2

votes

0

answers

18

views

Maximum ellipse inscribed in Witch of Agnesi curve

calculus geometry

modified 17 mins ago Ninad Munshi 12.3k

1

vote

1

answer

23

views

Polynomial-Exponential Equation

real-analysis sequences-and-series polynomials exponential-function

answered 18 mins ago p4sch 6,760

0

votes

0

answers

14

views

Show that a set of complex functions is finite

calculus complex-analysis

modified 18 mins ago Igor 89

0

votes

2

answers

22

views

How are the precise angles of a triangle found in terms of $\pi$ when the sides are given?

trigonometry

answered 19 mins ago kirti chauhan 11

0

votes

0

answers

4

views

Confidence interval $N(\theta,\theta)$

normal-distribution confidence-interval

asked 20 mins ago Le_Poisson 11

0

votes

0

answers

4

views

Derivatives of surface curvature

differential-geometry curvature

asked 21 mins ago Museful 685

1

vote

1

answer

12

views

Cartesian product of Kolmogorow spaces is also Kolmogorov space

general-topology

answered 23 mins ago mathcounterexamples.net 37.5k

0

votes

1

answer

18

views

Reference request: convergence for periodic Markov chains

reference-request markov-chains

modified 25 mins ago user8675309 2,044

2

votes

2

answers

27

views

Prove that there are infinitely many integers that are not of the form $n^3+2m^2$ for integers $m,n$. (Hint: Consider the situation modulo 8).

elementary-number-theory modular-arithmetic

answered 21 secs ago DanielWainfleet 43.6k

3

votes

1

answer

29

views

Is it true that for jordan block with zero eigenvalue we can choose basis where all diagonal elements are non zero?

linear-algebra jordan-normal-form

answered 27 mins ago Fabrizio 213

1

vote

2

answers

28

views

Restriction of surjective linear map is isomorphism

linear-algebra

modified 27 mins ago Bernard 148k

3

votes

0

answers

31

views

+50

Getting Rotation Matrix Using 3-Point Calibration

coordinate-systems symmetric-matrices

modified 28 mins ago Moayad Hani Abu Rmilah 81

1

vote

1

answer

8

views

Magnitudes of odds ratio and relative risk similar, what does this mean?

probability statistics

modified 28 mins ago StubbornAtom 11.1k

0

votes

2

answers

41

views

Finding isomorphism between two groups

group-theory group-isomorphism group-homomorphism quotient-group

modified 28 mins ago user750041 893

2

votes

1

answer

12

views

Does the integral of a function exist at a sharp point in the function?

functions

answered 32 mins ago csch2 2,494

0

votes

0

answers

4

views

Finite propagation speed of strictly hyperbolic equation

partial-differential-equations hyperbolic-equations linear-pde cauchy-problem

asked 35 mins ago WWC220023 1

3

votes

2

answers

1k

views

Another form of the Sandwich theorem (for derivatives in dimension $1$)

real-analysis proof-verification

modified 35 mins ago Community♦ 1

6

votes

5

answers

6k

views

Prove that one of $n$ consecutive integers must be divisible by $n$

elementary-number-theory

modified 36 mins ago robjohn♦ 294k

0

votes

1

answer

11

views

A question based on lower limit topology( 2nd countable, 1st countable)

general-topology analysis

modified 36 mins ago Kevin. S 1,477

0

votes

1

answer

19

views

Spivak Calculus chapter 1 question 14

algebra-precalculus proof-writing

answered 36 mins ago James 3,451

0

votes

0

answers

7

views

saddle point method with conjugate complex roots

asymptotics physics education statistical-mechanics large-deviation-theory

modified 37 mins ago user784507 1

1

vote

1

answer

32

views

Proving the map $f-i\cdot \text{id}_v$ is invertible with $f:V\to V$ a self-adjoint linear map

linear-algebra vector-spaces linear-transformations inner-product-space adjoint-operators

modified 39 mins ago darij grinberg 14.1k

0

votes

0

answers

9

views

prove integrable functions by means of Holder inequality

integration holder-inequality

asked 39 mins ago majid 81

0

votes

0

answers

6

views

exact sequence of sheaves extended by zero

algebraic-geometry

asked 39 mins ago Yu Ning 141

1

vote

1

answer

30

views

Rate convergence to fixed point of a function

fixed-point-theorems fixed-points

modified 39 mins ago Yves Daoust 170k

0

votes

1

answer

26

views

Sufficient statistic by factorization theorem

statistics probability-distributions statistical-inference log-likelihood data-sufficiency

modified 40 mins ago StubbornAtom 11.1k

0

votes

2

answers

16

views

Complement of multiplicative set is a (prime) ideal.

ideals

answered 41 mins ago Shivering Soldier 9,367

0

votes

0

answers

15

views

Resolution of a limit

analysis

asked 41 mins ago Ant2198 37

3

votes

1

answer

101

views

+50

Can convolution be expressed as a differential equation?

calculus ordinary-differential-equations convolution

answered 43 mins ago user619894 1,414

0

votes

0

answers

9

views

Euclidean geometry- how do I finish this proof

contest-math euclidean-geometry

asked 47 mins ago MNIShaurya 480

3

votes

0

answers

45

views

Prove that bounded function with midpoint convex is continuous

calculus continuity jensen-inequality

modified 53 mins ago ToBY 840

1

vote

1

answer

15

views

Conditions that a function is analytic in the complex plane of its independent variable?

complex-analysis functions definition

answered 53 mins ago WA Don 1,275

2

votes

2

answers

39

views

Evaluate $\sum_{n=1}^{50}n\cdot n!$.

sequences-and-series summation factorial

modified 55 mins ago El borito 795

0

votes

0

answers

17

views

Issue with cylindrical integration

integration multivariable-calculus cylindrical-coordinates

asked 56 mins ago Charles Cooper 25

3

votes

1

answer

33

views

Number of $2 \times 2$ matrices over the finite field $\mathbb{F}_q$ whose minimal polynomial is divisible by $X-1$.

linear-algebra matrices vector-spaces linear-transformations finite-fields

modified 57 mins ago user26857 41.7k

4

votes

1

answer

38

views

Is it safe to say the following about the odd prime numbers other than 5.

arithmetic

modified 58 mins ago Anvit 3,094

0

votes

0

answers

26

views

Depth of $i$-th syzygy module, where $i$ is at most the depth of the ring

commutative-algebra homological-algebra

modified 59 mins ago user26857 41.7k

1

vote

0

answers

9

views

Comparing explicit generators of the $n$-th singular homology group of $S^n$.

algebraic-topology homology-cohomology

asked 1 hour ago Colescu 6,663

0

votes

0

answers

34

views

How to check if the series is analytic?

sequences-and-series complex-analysis number-theory analytic-number-theory analytic-functions

modified 1 hour ago Kashif 33

1

vote

0

answers

11

views

Lipschitz by Stone-Weierstrass

analysis holder-spaces weierstrass-approximation

asked 1 hour ago defenestrator 416

4

votes

1

answer

55

views

+50

Find shortest path in undirected complete n-partite graph that visits each partition exactly once

graph-theory algorithms

answered 1 hour ago Alex Ravsky 59.2k

-1

votes

0

answers

8

views

$SL_4(\mathbb R)$ as a subgroup of $SL_3(\mathbb C)$

group-theory lie-groups lie-algebras algebraic-groups

asked 1 hour ago June 61

0

votes

0

answers

18

views

Flux through cone revisited

multivariable-calculus vector-analysis vector-fields divergence-theorem

modified 1 hour ago Peter 118

3

votes

0

answers

36

views

Questions about cohomology and cocycles in Munkres's book and my attempt to find cocycles in $n$-fold dunce cap

algebraic-topology solution-verification homology-cohomology

modified 1 hour ago Kevin. S 1,477

1

vote

0

answers

9

views

A question related to tensor product of $R$-modules

abstract-algebra ring-theory modules tensor-products flatness

modified 1 hour ago Sumanta 3,667

0

votes

0

answers

8

views

test spaces and variational formulation in finite elements for elliptic problems

sobolev-spaces boundary-value-problem weak-derivatives finite-element-method

modified 1 hour ago giorgio pulvirenti 1

0

votes

0

answers

24

views

find points close to targets, but at least min_dist apart

optimization convex-optimization

modified 1 hour ago Nico Schlömer 824

0

votes

0

answers

10

views

A compact hyperbolic manifold and fundmental group

differential-geometry hyperbolic-geometry fundamental-groups

asked 1 hour ago Chern 1

0

votes

0

answers

27

views

Counting four-letter words formed from the letters of ENGLISH that start with E and have no repeated letters

combinatorics permutations

modified 1 hour ago Blue 58.1k

0

votes

0

answers

20

views

N Balls in two urns

probability conditional-probability balls-in-bins

asked 1 hour ago Francesco Totti 53

-1

votes

0

answers

14

views

Density of tensor products of eventually zero sequences.

real-analysis sequences-and-series functional-analysis

modified 1 hour ago Prof.Hijibiji 184

0

votes

0

answers

13

views

Triangle of maximal area with vertices origin and intersections of a chord with a curve

calculus

asked 1 hour ago DDD4C4U 449

0

votes

0

answers

18

views

The boundedness of a determinant

linear-algebra determinant

asked 1 hour ago ling 757

0

votes

2

answers

44

views

What is the sum of n terms 1.5.9+5.9.13+9.13.17…?

sequences-and-series

modified 1 hour ago Arnav Mahajan 142

7

votes

0

answers

131

views

+500

How to utilize the special feature of this recursive problem to reduce computational complexity?

reference-request algorithms matrix-equations numerical-linear-algebra recursive-algorithms

modified 1 hour ago LAD 5,386

2

votes

1

answer

18

views

$A \subset B$ be a faithfully flat extension of domains and $B$ is integrally closed then $A$ is also integrally closed.

commutative-algebra flatness integral-extensions

answered 1 hour ago Youngsu 2,591

0

votes

0

answers

16

views

Prove that M is a martingale

stochastic-processes stochastic-calculus martingales local-martingales

asked 1 hour ago Ivan Petrov 1

0

votes

0

answers

19

views

$(A-x) \cdot (B-x) \cdot (C-x) = V. \space$ Is it possible to isolate $ \space x$?

computer-science computational-mathematics

modified 1 hour ago Anton Vrdoljak 1,139

3

votes

0

answers

24

views

Is the Cesàro sum of the Fourier series of $f$ a best approximation of $f$ in any sense?

soft-question fourier-analysis harmonic-analysis summation-method cesaro-summable

modified 2 hours ago Bob 3,488

2

votes

1

answer

45

views

Closed form of $\int_0^\infty \arctan^2 \left (\frac{2x}{1 + x^2} \right ) \, dx$

integration definite-integrals closed-form

answered 2 hours ago Zacky 20.3k

0

votes

0

answers

10

views

Find the maximum of piece-wise multivariate function?

multivariable-calculus optimization piecewise-continuity

asked 2 hours ago Cong 3

0

votes

0

answers

15

views

Covariance of squared terms

probability probability-distributions covariance

asked 2 hours ago HUM 1

2

votes

1

answer

17

views

Unit of a monoid object in a monoidal category

abstract-algebra category-theory

answered 2 hours ago asdq 2,883

1

vote

0

answers

7

views

if such counter example to Lehmer's totient problem exists then could we have more counter examples?

arithmetic-functions primality-test lucas-lehmer-test

asked 2 hours ago zeraoulia rafik 5,899

2

votes

1

answer

28

views

Expected value of absolute value of centered random variable

probability expected-value jensen-inequality

modified 2 hours ago Michael 16.6k

3

votes

1

answer

28

views

Ways to fill up a $4 \times 4$ matrix with numbers $1$ to $16$, s.t its rank is $1$ under modulo $17$

combinatorics generating-functions

answered 2 hours ago saulspatz 34.7k

0

votes

1

answer

20

views

$f(X_n)\to f(x_0)\Rightarrow X_n\to x_0$

probability probability-theory convergence-divergence

answered 2 hours ago Michael 16.6k

7

votes

1

answer

73

views

Two sentences with same consequences

logic

modified 3 hours ago Noah Schweber 165k

1

vote

1

answer

98

views

smooth affine algebraic curves and their subschemes

algebraic-geometry algebraic-curves dedekind-domain

modified 3 hours ago Armando j18eos 3,013

-1

votes

1

answer

21

views

Prove the following sum identity by induction

induction

answered 3 hours ago person 81

2

votes

1

answer

28

views

$ \mathbb{R} $ with the $ K $-topology ($ \mathbb{R}_{K} $)

general-topology

answered 4 hours ago Henno Brandsma 165k

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