Mathematics Stack Exchange

0

votes

1

answer

17

views

Is $K_a$ subspace of vector space $V$?

real-analysis linear-algebra elementary-set-theory linear-transformations set-theory

modified 2 mins ago Kevin López Aquino 135

0

votes

0

answers

2

views

Rolling dices and Poisson distruibition

probability poisson-distribution dice

asked 2 mins ago Guotai Shen 1

0

votes

1

answer

12

views

The derivative of the absolute value function

calculus absolute-value convention

answered 1 min ago Andrew Chin 5,160

0

votes

1

answer

9

views

In a finite difference model for a vibrating string, how does the number of mesh points predict how many modes can be produced?

ordinary-differential-equations partial-differential-equations wave-equation

answered 4 mins ago K.defaoite 2,622

-3

votes

0

answers

18

views

The limit ${\lim_{x\rightarrow 1}\frac{9^{3^{2\ln(x)}}-9^{2^{\ln(x)}}}{\ln(x)}}$

calculus derivatives continuity

modified 4 mins ago Riemann'sPointyNose 2,034

7

votes

4

answers

122

views

Integrate $\frac{\theta \sin \theta}{1+\cos^2 \theta}$ with respect to $\theta$

calculus integration definite-integrals

modified 5 mins ago Ty. 4,170

0

votes

1

answer

22

views

Find the static moments about the coordinate axes of a segment of the straight line $\frac{x}{a} + \frac{y}{b} = 1$

calculus definite-integrals

modified 7 mins ago Andrei 22.1k

0

votes

0

answers

27

views

How to construct such a line as $l$?

geometry contest-math geometric-construction

modified 7 mins ago Eric Monlye 82

4

votes

2

answers

87

views

Something like the trace of a tensor

riemannian-geometry tensors semi-riemannian-geometry

modified 13 mins ago Yuri Vyatkin 8,568

2

votes

1

answer

34

views

Jordan normal form of powers of Jordan normal form

linear-algebra matrices matrix-decomposition jordan-normal-form

modified 14 mins ago Stephen Montgomery-Smith 19.3k

2

votes

1

answer

52

views

Integrating $\int_0^1 \frac{\ln(1+x)\ln^3 x}{1+x}\,dx$ with restricted techniques

calculus integration sequences-and-series harmonic-numbers

modified 15 mins ago Ali Shather 14.7k

0

votes

0

answers

21

views

What is the formula for the blue plot?

algebra-precalculus order-theory

modified 17 mins ago ie86 369

0

votes

0

answers

10

views

Derivative of resultant axis-angle with respect to two consecutive axis-angle rotations

derivatives differential-geometry partial-derivative rotations

asked 17 mins ago Shawn Wang 137

0

votes

0

answers

6

views

How should I find this derivative?

derivatives density-function

asked 18 mins ago Strakatastic 330

1

vote

1

answer

18

views

Number of chains with size $k$ in a symmetric chain paritition of subsets of $\{1,2,…,n\}$.

combinatorics

modified 18 mins ago Eric Monlye 82

0

votes

1

answer

18

views

Find linear transformation matrix given equation and bases

linear-algebra matrices linear-transformations

modified 22 mins ago Eric Monlye 82

0

votes

0

answers

8

views

Conditional distribution $e|x$

probability probability-distributions conditional-probability

modified 22 mins ago Eric Monlye 82

1

vote

1

answer

25

views

Finding cosets of a subgroup of $S_{3}$

abstract-algebra group-theory symmetric-groups

modified 23 mins ago Antoni Parellada 5,609

1

vote

1

answer

19

views

what is the circle bundle of $\mathbb{R}^2$

differential-geometry riemannian-geometry

modified 25 mins ago Ivo Terek 59.6k

0

votes

1

answer

41

views

If for a complex function if $f^{(n)}(1/k)=0$ $\forall k \in \mathbb{N}$, then $f(z)$ is a polynomial

complex-analysis polynomials solution-verification

modified 29 mins ago Subhasis Biswas 2,156

2

votes

1

answer

25

views

Integration of $\int_{\mathbb{R}} e^{-\pi(x+i\xi)^2} dx$?

complex-analysis

answered 31 mins ago SaMaSo 116

0

votes

0

answers

8

views

Sum of the power of product of partitions

calculus analysis

asked 33 mins ago Cech Cohomology 505

4

votes

1

answer

28

views

Heisenberg group modulo prime

abstract-algebra group-theory group-presentation heisenberg-group

modified 34 mins ago Shaun 23.6k

2

votes

1

answer

12

views

Choosing a “canonical” representant of a class of measurable functions based on the essential range

measure-theory lebesgue-measure measurable-functions borel-measures

answered 36 mins ago Eric Wofsey 242k

0

votes

0

answers

38

views

Resources for a topic in geometry.

contest-math online-resources

modified 38 mins ago Aayam Mathur 487

2

votes

0

answers

13

views

For integral domains $R$ and $S$, If $S \sim R^n$, does $Quot(S) / Quot(R)$ have degree $n$?

abstract-algebra field-theory integral-domain

asked 39 mins ago David Lui 1,110

2

votes

2

answers

50

views

Find the locus of $\frac{\pi}{3}\le \arg(-z+3+i)\le \frac{5\pi}{3}$

calculus complex-numbers

modified 39 mins ago Matt Samuel 52.8k

0

votes

0

answers

13

views

If Lebesgue integral of nonnegative measurable function on $[0,x]$ is one-to-one, is $f$ positive almost everywhere?

real-analysis measure-theory lebesgue-integral lebesgue-measure

modified 44 mins ago Kavi Rama Murthy 203k

1

vote

1

answer

95

views

Meaning of a locus.

complex-numbers locus

modified 44 mins ago UmbQbify -Key20- 789

0

votes

0

answers

17

views

Smallest integer that is not a sum of three or fewer elements of a prime set (with replacement)

elementary-number-theory prime-numbers contest-math

asked 49 mins ago Michalis Paizanis 3

3

votes

1

answer

175

views

Remark in Hatcher's Algebraic Topology on Mapping Cylinders

algebraic-topology

answered 51 mins ago Alex Ortiz 13.7k

2

votes

0

answers

89

views

Defining the argument of a complex number at origin

complex-numbers

modified 55 mins ago UmbQbify -Key20- 789

0

votes

1

answer

17

views

Are Semiregularity and Complete Hausdorff Properties preserved by Products

general-topology separation-axioms product-space

answered 1 hour ago Brian M. Scott 508k

2

votes

0

answers

53

views

+50

How to calculate matrix divergence in polar coordinates

polar-coordinates divergence-operator

modified 1 hour ago Please correct GrammarMistakes 185

1

vote

2

answers

19

views

General formula for the number of terms from when evaluating the product of n terms $\Pi_{i=1}^{n}(1+x_i)^n$?

combinatorics summation combinations

modified 1 hour ago Phicar 6,724

3

votes

1

answer

32

views

Prove that $a$ commutes with each of its conjugates in $G$ if and only if a belongs to an abelian normal subgroup of $G$.

abstract-algebra group-theory solution-verification abelian-groups normal-subgroups

answered 1 hour ago Stahl 18.8k

0

votes

2

answers

24

views

Does a Lebesgue measurable set E exist with this property?

real-analysis measure-theory lebesgue-measure radon-nikodym

answered 1 hour ago JCAA 4,245

2

votes

1

answer

857

views

Proving that a given group action is Transitive.

abstract-algebra group-theory

modified 1 hour ago Community♦ 1

0

votes

1

answer

11

views

Is the Random Variable's Expectation the optimal Solution for the Mean Squared Error?

optimization expected-value mean-square-error

answered 1 hour ago Mushu Nrek 378

0

votes

0

answers

17

views

What algorithms exist for Polynomial Interpolation of arbitrary degree in two variables.

polynomials finite-fields interpolation interpolation-theory

modified 1 hour ago Kirk 1

0

votes

2

answers

43

views

Reflection of point over line with absolute value

geometry functions

answered 1 hour ago Eric Liang 5

2

votes

0

answers

25

views

Problem in Allen-Cahn equation: How to get the maximum norm of $f(\vec{w}) = \vec{w} + c (\vec{w} - W (W^{-1} \vec{w})^{3})$, is it always $\leq 1$?

linear-algebra functional-analysis partial-differential-equations normed-spaces maximum-principle

modified 1 hour ago sky walker 73

3

votes

2

answers

32

views

Optimal Betting Strategy question

probability probability-theory

answered 1 hour ago Ross Millikan 340k

1

vote

1

answer

24

views

Characterizing a “like” normal matrix

matrices complex-analysis functional-analysis

answered 1 hour ago William Bell 376

0

votes

0

answers

57

views

Dominate any positive function from a topological space by a series of compactly supported functions

general-topology continuity compactness

modified 1 hour ago h3fr43nd 452

1

vote

1

answer

18

views

Find formula for linear transformation given matrix and bases

linear-algebra matrices linear-transformations

answered 1 hour ago Phicar 6,724

1

vote

1

answer

22

views

Question on Hölder's inequality when it's equal

integration measure-theory holder-inequality

answered 1 hour ago user1691278 1,013

3

votes

1

answer

45

views

Show $\forall c>0$ have $\int^b_af(x)dx=c\int^{b/c}_{a/c}f(cx)dx$ from the definition of integral

calculus integration definition

modified 1 hour ago Koro 2,423

3

votes

2

answers

37

views

$q-p$ is a projection when $pq = p$

functional-analysis operator-theory hilbert-spaces c-star-algebras projection

answered 1 hour ago Martin Argerami 153k

0

votes

1

answer

22

views

Two types of proofs conditional expectation.

probability expected-value conditional-expectation

answered 1 hour ago Kavi Rama Murthy 203k

2

votes

0

answers

103

views

Equation of circle through 3 non collinear complex points.

complex-numbers circles

modified 1 hour ago UmbQbify -Key20- 789

0

votes

0

answers

40

views

An elementary 'bare bones' $\text{ZF}$ construction of the natural numbers?

logic set-theory axioms foundations natural-numbers

modified 1 hour ago CopyPasteIt 8,364

1

vote

0

answers

5

views

UMP Test for $f_{\theta}(x)=2\theta^{-2}(\theta-x)I_{(0,\theta)}(x)$

statistics hypothesis-testing

asked 1 hour ago Noe Vidales 679

0

votes

1

answer

23

views

What is the relationship between $p$-norm and 2-norm for any $p$-norm?

real-analysis linear-algebra optimization vector-spaces norm

answered 1 hour ago uniquesolution 13.5k

0

votes

1

answer

31

views

Product of two absolutely continuous measures

functional-analysis probability-theory measure-theory

modified 1 hour ago LL 3.14 3,086

1

vote

1

answer

10

views

Show that $P:\mathbb{R}^k\to\mathbb{R}$ by $P(x_1,…,x_k)=\sum_{(i_1,…,i_k)\in I}c(i_1,…,i_k)x_1^{i_1}\cdot\cdot\cdot x_k^{i_k}$ is continuous.

real-analysis continuity

answered 1 hour ago Kavi Rama Murthy 203k

5

votes

1

answer

70

views

Trees in which every vertex is a leaf or adjacent to a leaf

graph-theory terminology trees

modified 1 hour ago Elmar Guseinov 491

0

votes

1

answer

36

views

Evaluating the integral $\int_{f}^{g} \exp \left[-\frac{1}{d}\left(c+b x+a x^{2}\right)\right] d x$

integration exponential-function

modified 1 hour ago hwood87 104

2

votes

1

answer

77

views

Deforming contour in complex plane integration and wave equation

complex-analysis partial-differential-equations complex-integration wave-equation

modified 1 hour ago Joe Mack 339

0

votes

1

answer

22

views

Z-Score +Table Usage

statistics normal-distribution

modified 2 hours ago BruceET 40.8k

3

votes

2

answers

45

views

What's the MacLaurin series of $f(x)=x\ln\left(1+\dfrac{x}3\right)$?

calculus sequences-and-series taylor-expansion

modified 2 hours ago James A 1,321

7

votes

1

answer

232

views

Roots of $x+\frac 1x=2e^{i\phi}$

algebra-precalculus complex-numbers

modified 2 hours ago UmbQbify -Key20- 789

1

vote

0

answers

16

views

Proof of continuity of parametric integral

integration definite-integrals continuity riemann-integration

asked 2 hours ago Philipp 964

2

votes

0

answers

28

views

How to solve the complex line integral $\int_C \overline{z}^2 dz + z^2 d\overline{z}$?

complex-analysis complex-integration line-integrals

modified 2 hours ago RobPratt 13.7k

2

votes

1

answer

19

views

Find a counter example that if $X$ banach space is not reflexive , the the operator doesn't have to be compact

functional-analysis banach-spaces

modified 2 hours ago RobPratt 13.7k

1

vote

1

answer

47

views

Open-source notes to Basic Algebra by Jacobson

abstract-algebra self-learning

answered 2 hours ago Anonymous 1

0

votes

0

answers

18

views

Solve the system by RREF (parametric form)

linear-algebra gaussian-elimination

asked 2 hours ago Laufen 401

1

vote

0

answers

37

views

+100

If $B$ is a $C^*$-subalgebra of $A$, then $\sigma_A(b) \cup \{0\} = \sigma_B(b) \cup \{0\}$

functional-analysis operator-theory solution-verification c-star-algebras

modified 2 hours ago user745578 730

0

votes

1

answer

35

views

Construction of random variables with symmetric matrices

probability inequality

answered 2 hours ago kimchi lover 19.3k

1

vote

0

answers

49

views

Size constraints on reduced solutions to $x^p\equiv 1\mod q$

number-theory primitive-roots

modified 2 hours ago Eric Wofsey 242k

2

votes

2

answers

82

views

What is the probability space of typical real univariate probability distributions?

probability-theory measure-theory probability-distributions category-theory lebesgue-measure

modified 2 hours ago ir7 4,922

0

votes

0

answers

19

views

Is this a valid manipulation for differential operators?

ordinary-differential-equations differential-operators

modified 2 hours ago defarm 63

1

vote

0

answers

20

views

How to solve this problem of Numerical Differentiation

numerical-methods

modified 2 hours ago Iesus Dave Sanz 13

2

votes

2

answers

16

views

Recurrence and ergodicity for non-measure preserving transforms

dynamical-systems ergodic-theory

modified 2 hours ago Lee Mosher 72.3k

0

votes

2

answers

61

views

Orthocenter of triangle with vertices on the hyperbola is also on the hyperbola

linear-algebra triangles conic-sections

modified 2 hours ago Maximilian Janisch 8,943

0

votes

1

answer

19

views

How can I convert a certain rating score by using the following information? (picture included)

statistics normal-distribution gaussian

answered 2 hours ago BruceET 40.8k

1

vote

1

answer

26

views

Is “each player always defects” a Nash equilibrium in Iterated Prisoners Dilemma

game-theory

answered 2 hours ago Herr K. 1,063

0

votes

0

answers

9

views

Convexity of affine function nested in log-sum-exp

real-analysis convex-analysis convex-optimization

modified 2 hours ago JYY 135

0

votes

0

answers

14

views

On the relationship between orthogonal geometry and circuit geometry of a matrix

linear-algebra orthogonality combinatorial-geometry matroids

modified 2 hours ago Lucio Tanzini 1,090

0

votes

0

answers

18

views

Different answers when changing variables in a definite integral with an infinite lower limit

calculus integration limits definite-integrals substitution

asked 3 hours ago ForeverStudent 1

0

votes

1

answer

8

views

Can the topology of a quad mesh with irregular vertices be represented as a square grid graph?

general-topology graph-theory computational-geometry

modified 3 hours ago Hagen von Eitzen 322k

1

vote

1

answer

56

views

+50

Poisson equation with stochastic source

distribution-theory dirac-delta poissons-equation stochastic-pde

answered 3 hours ago md2perpe 13.9k

1

vote

1

answer

34

views

Vector calculus and undefined operations

calculus linear-algebra multivariable-calculus vector-analysis

answered 3 hours ago greg 16.3k

2

votes

0

answers

29

views

Question about the meaning of an important footnote to entry 109 in Gauss's diary

math-history modular-forms

modified 3 hours ago user2554 291

1

vote

0

answers

29

views

Geometry of Riemannian quotient manifold $St(\mathbb{C}^{n \times p},B)/U(1)^{\times p}$

riemannian-geometry

modified 3 hours ago cjferes 1,694

1

vote

1

answer

13

views

Example of Semiregular and $T_1$ Space which is not Hausdorff

general-topology separation-axioms

answered 3 hours ago Brian M. Scott 508k

1

vote

0

answers

37

views

How to calculate $\left(\bigcup_i A_i\right) \setminus B$

elementary-set-theory

asked 3 hours ago Eduude 775

1

vote

0

answers

28

views

Rational integral representation of inverse logarithm.

real-analysis calculus integration multivariable-calculus

modified 3 hours ago Alex R. 28.9k

-1

votes

0

answers

29

views

Stone-Weiertrass density theorem

real-analysis analysis

modified 4 hours ago Bernard 152k

0

votes

0

answers

17

views

Modifying generating functions to work for cases with distinct objects

generating-functions

modified 4 hours ago DDD4C4U 787

2

votes

0

answers

36

views

Cat's curve and some properties

derivatives soft-question curves

modified 4 hours ago Mark McClure 25.8k

0

votes

0

answers

31

views

Notion of absolute continuity of an orthogonal stochastic measure?

probability-theory measure-theory stochastic-processes

modified 4 hours ago Joe Mack 339

1

vote

2

answers

31

views

How do we interpret a zero sequence in the context of ideal theory?

abstract-algebra ring-theory ideals cauchy-sequences

answered 4 hours ago Carlo 3,193

4

votes

0

answers

47

views

Let $K$ be a Galois extension of $\mathbb{Q}$.

abstract-algebra galois-theory extension-field symmetric-groups galois-extensions

modified 4 hours ago Vercassivelaunos 1,098

0

votes

2

answers

2k

views

Asymptotic variance of MLE of normal distribution.

probability statistics asymptotics statistical-inference estimation

modified 5 hours ago Community♦ 1

2

votes

0

answers

27

views

Exercise 10 in 1.1 (page 4) of Topology and Groupoids, by Ronald Brown

general-topology real-numbers

asked 5 hours ago Novice 195

Jun	JUL	Aug
	20
2019	2020	2021

Explore our Questions