Mathematics Stack Exchange

0

votes

0

answers

8

views

Linear operators on vectors are Tensors?

vectors tensors

modified 2 mins ago User 10482 101

0

votes

1

answer

11

views

Shortest Path Passing Through All Points When Start and End Points are Given

graph-theory computational-complexity

modified 2 mins ago Rob Pratt 10.2k

1

vote

0

answers

4

views

How to find subgroups?

abstract-algebra group-theory

asked 3 mins ago Plenti192 11

1

vote

0

answers

3

views

Proving that two subspace are orthogonal by the fact that the projection transformation satisfies: $P = P*$

linear-algebra transformation

asked 3 mins ago Alon 689

0

votes

0

answers

3

views

Probability of two consecutive heads

probability probability-theory discrete-mathematics

asked 3 mins ago Fish_n_Chips 23

1

vote

0

answers

9

views

How to find all generators for a cyclic group of order n?

abstract-algebra group-theory cyclic-groups

asked 8 mins ago Heinrich Jensen 109

2

votes

1

answer

16

views

Holomorphic function such that $f(1/n)=1/n^2$, not $z^2$

complex-analysis

answered 1 min ago Gae. S. 7,857

0

votes

0

answers

8

views

Convergence of an infinite sequence of Bernoulli trails

probability probability-theory convergence-divergence

modified 9 mins ago Bernard 145k

0

votes

0

answers

4

views

Covering number of an $l_2$-ball

probability

asked 9 mins ago kkc 753

0

votes

0

answers

25

views

Determine $\lim_{n\rightarrow\infty}\sum\limits_{k=1}^n\frac{\sin(\frac{a}{3^k})}{3^k\sin(\frac{a}{3^{k-1}})}$

calculus limits

modified 29 secs ago Micah Windsor 125

1

vote

1

answer

33

views

summation of series (binomial theorem)

combinatorics summation negative-binomial

modified 9 mins ago Rob Pratt 10.2k

0

votes

0

answers

6

views

Rearranging variables in summation notation

algebra-precalculus summation summation-method

asked 9 mins ago Mike 1

0

votes

6

answers

35

views

Compare $-2$ and $2-\sqrt{3}$

inequality

answered 10 mins ago amd 43k

1

vote

0

answers

42

views

Exercise on meromorphic forms of the Riemann sphere

solution-verification differential-forms riemann-surfaces meromorphic-functions

modified 13 mins ago Something 1,347

1

vote

1

answer

27

views

+50

Calculate effective interest including fees, mortgages and nominal interest

finance

answered 14 mins ago Mark 814

0

votes

1

answer

10

views

Gal$(X^2-X-1, X^9-X) ⊆ S_2, S_9$

abstract-algebra field-theory galois-theory finite-fields

modified 1 min ago qualcuno 11.7k

2

votes

1

answer

19

views

Show that there are no compact surfaces that have negative Gauss curvature everywhere

linear-algebra differential-geometry surfaces

answered 16 mins ago Ted Shifrin 76.9k

1

vote

0

answers

8

views

Product rule for codifferential on manifolds

differential-geometry smooth-manifolds differential-forms

modified 18 mins ago Eduardo Longa 3,288

0

votes

0

answers

6

views

Is this $2$-form harmonic?

differential-geometry riemannian-geometry harmonic-functions

asked 19 mins ago Eduardo Longa 3,288

0

votes

2

answers

12

views

The split of conjugate classes of $A_4$

group-theory symmetric-groups

answered 19 mins ago user766588 1

2

votes

0

answers

18

views

Steady state of a system of ordinary differential equations

ordinary-differential-equations systems-of-equations self-learning mathematical-modeling

modified 21 mins ago keyring 21

0

votes

0

answers

23

views

Least squares multivariate polynomial coefficient fitting

least-squares multivariate-polynomial

modified 23 mins ago darron 101

1

vote

2

answers

17

views

The negation of $(P)$

measure-theory

answered 23 mins ago CR Drost 2,175

0

votes

0

answers

11

views

Higher order directional derivatives

real-analysis

asked 23 mins ago ajaaaaaa 31

2

votes

1

answer

31

views

Can the Fenchel conjugate be characterized through the Fenchel-Young inequality?

convex-analysis convex-optimization duality-theorems

modified 24 mins ago dohmatob 4,898

0

votes

2

answers

19

views

What is a function that converts any number to a one, while keeping the sign intact?

algebra-precalculus functions

answered 26 mins ago Matteo 2,928

13

votes

1

answer

271

views

Evaluate $\int_{(-\infty,\infty)^n}\frac{\prod_{k=1}^n \sin(a_k x_k)}{\prod_{k=1}^n x_k}\frac{\sin(\sum_{k=1}^n a_k x_k)}{\sum_{k=1}^n a_k x_k}$

integration definite-integrals

modified 26 mins ago metamorphy 12.9k

1

vote

3

answers

33

views

Student Seeking Beginning Calculus Advice

calculus linear-algebra algebra-precalculus self-learning advice

modified 27 mins ago J. W. Tanner 33.3k

3

votes

2

answers

28

views

Jordan matrix of $A$ and $A^{-1}$

linear-algebra

answered 27 mins ago Will Jagy 115k

0

votes

0

answers

5

views

linear matrix equation of PSD matrix

linear-algebra matrix-equations symmetric-matrices pseudoinverse

modified 31 mins ago hichem hb 11

0

votes

0

answers

7

views

Does there exist a k-Sassy number with $2^{k-1}$ positive divisors?

number-theory prime-numbers

asked 31 mins ago Perry Ainsworth 171

0

votes

0

answers

7

views

Projection onto a subspace in an $L_p$ normed space

lp-spaces normed-spaces angle projection gram-schmidt

asked 31 mins ago Tolga Birdal 353

1

vote

0

answers

6

views

Can numbers of any arbitrary irrationality measure be generated?

irrational-numbers irrationality-measure

asked 32 mins ago samerivertwice 6,866

1

vote

0

answers

21

views

Hyperelliptic Riemann surfaces

differential-forms algebraic-curves riemann-surfaces

modified 33 mins ago Something 1,347

2

votes

1

answer

28

views

Evaluate:$\sum_{s=0}^{N}(-1)^s{2s \choose s}{N+s \choose N-s}\frac{s^2}{(s+1)^2}$

summation binomial-coefficients

answered 35 mins ago Marko Riedel 47.6k

3

votes

0

answers

27

views

The Functional-Calculus Version of the Spectral Theorem

functional-analysis analysis spectral-theory

modified 35 mins ago LinearGuy 122

0

votes

1

answer

18

views

Find density of a random variable

probability probability-theory

answered 36 mins ago Dasherman 1,412

0

votes

0

answers

15

views

Equations and inequalities with a parameter!

inequality

asked 37 mins ago Jonathan Diamond 1

2

votes

0

answers

20

views

Pullback of 2 functors one of which creates limits and the other preserves

category-theory limits-colimits pullback

modified 38 mins ago jgon 22.3k

0

votes

0

answers

5

views

Calculate the standard deviation of a normal distributed histogram without the frequencies?

normal-distribution

modified 39 mins ago pvestia 25

2

votes

0

answers

13

views

Trying to understand an application of Hahn Banach extension theorem

linear-algebra dual-spaces hahn-banach-theorem

asked 40 mins ago Meep 2,376

0

votes

0

answers

6

views

Cauchy Interlace Theorem for diagonalizable matrices (over $\mathbb{C}$)

spectral-theory diagonalization

asked 41 mins ago Television 508

0

votes

0

answers

23

views

Order proof using axiomatic

real-numbers

modified 42 mins ago J. W. Tanner 33.3k

-1

votes

0

answers

12

views

Quadratic variation-Brownian Motion

probability-theory stochastic-processes stochastic-integrals stochastic-analysis

modified 42 mins ago snipherr 1

1

vote

2

answers

9

views

What is the coordinate vector of x relative to B?

linear-algebra coordinate-systems

answered 45 mins ago zugzug 2,234

0

votes

0

answers

6

views

The problem of determining whether a given context-free grammar generates the empty string

context-free-grammar turing-machines

asked 46 mins ago Emily Bennett 1

0

votes

0

answers

12

views

The error size of discrete approximation to a optimal control problem

optimal-control discrete-optimization

modified 47 mins ago user391830 153

26

votes

4

answers

4k

views

If $E[X|Y]=Y$ almost surely and $E[Y|X]=X$ almost surely then $X=Y$ almost surely

probability-theory conditional-expectation

answered 53 mins ago mathex 478

0

votes

0

answers

18

views

A singleton vector is a linear independent set if and only if it is not the zero vector. (Proof Verification)

linear-algebra solution-verification

asked 56 mins ago user10360304 1

1

vote

0

answers

14

views

Invariance Of Inner Product and Quadratic Forms

linear-algebra

modified 56 mins ago 1729_SR 19

1

vote

1

answer

9

views

calculating allowable paths

combinatorics binomial-coefficients multinomial-coefficients

answered 57 mins ago Parcly Taxel 56.4k

0

votes

0

answers

11

views

If a probability density function has a limit at infinity, is that limit always zero?

probability probability-theory probability-distributions probability-limit-theorems

asked 58 mins ago Galen 255

1

vote

0

answers

4

views

Defining a seminorm for trace-class operators using bounded operators

functional-analysis operator-theory compact-operators

asked 1 hour ago X.Y. 11

2

votes

2

answers

33

views

Prove $(x^a-1)(y^b-1)\geq (1-x^{-b})(1-y^{-a})$ where $x,y\geq 1$ and $a,b \geq 0$.

algebra-precalculus analysis multivariable-calculus inequality

answered 1 hour ago Calum Gilhooley 6,229

0

votes

0

answers

10

views

How to show Laplace's equation is invariant to spherical inversion?

pde harmonic-functions

asked 1 hour ago Physiks lover 111

3

votes

1

answer

20

views

Projective objects in functor categories

homological-algebra abelian-categories

answered 1 hour ago Zeek 639

-1

votes

0

answers

6

views

How do you find the volume obtained by rotating $0≤y≤8√x - x²$ about the $y$-axis within $0≤x≤π$?

integration complex-integration

modified 1 hour ago Teddy38 2,232

1

vote

0

answers

10

views

Nuclear norm bounded by Frobenius norm

linear-algebra matrices matrix-norms

asked 1 hour ago RLC 501

0

votes

0

answers

18

views

difficult problem on graph theory

combinatorics

asked 1 hour ago Mike Druther 41

0

votes

0

answers

5

views

What is the “best” product rule for finite difference computations?

derivatives numerical-methods numerical-linear-algebra computational-mathematics numerical-calculus

asked 1 hour ago Aguichine Artyom 1

1

vote

1

answer

14

views

Questions about completely normal spaces.

general-topology separation-axioms order-topology sorgenfrey-line

answered 1 hour ago Brian M. Scott 479k

0

votes

0

answers

8

views

check whether a process is strongly markovian

probability-theory stochastic-processes markov-chains markov-process

modified 1 hour ago Bernard 145k

0

votes

0

answers

10

views

Sum of the first n-th roots of z, $\sum_n z^{1/n}$, L-function with rational powers.

sequences-and-series power-series special-functions l-functions l-series

asked 1 hour ago Dr Potato 183

0

votes

0

answers

9

views

find canonical form of $ u_{tt}+(c+d)u_{xt}+(cd)u_{xx}=0$ (hyperbolic)

pde hyperbolic-equations

modified 1 hour ago Empty 1

2

votes

1

answer

23

views

Lemniscate - two parametrizations

differential-geometry curves parametrization

modified 1 hour ago robjohn♦ 289k

1

vote

0

answers

33

views

Frobenius isomorphism

abstract-algebra

modified 1 hour ago Robert Lewis 58.6k

1

vote

0

answers

17

views

Class of all sigma fields that contain $\mathbf{C}$

real-analysis probability-theory measure-theory

modified 1 hour ago Masoud 1,335

4

votes

1

answer

23

views

Why is the interior of $\{(x_n)_n \in {\displaystyle \ell ^{2}}| \sum_{n=1}^{\infty}n^2|x_n|^2 < \infty\}$ empty?

functional-analysis

modified 1 hour ago Learning 2,929

0

votes

0

answers

11

views

checking is a point lies inside the area enclosed by multiple equations using linear algebra

linear-algebra matrices

asked 1 hour ago InAFlash 121

2

votes

1

answer

55

views

+50

Proving that a diagram involving associators and unitors commutes in a bicategory

category-theory monoidal-categories higher-category-theory 2-categories bicategories

answered 1 hour ago Chessanator 3,122

1

vote

1

answer

18

views

if $x^x=y^y$, and $x>0$ and $y>0$, solve for y in terms of x or prove this impossible

algebra-precalculus

answered 1 min ago Aidan 592

0

votes

0

answers

9

views

How many combinations of pairs of sets I get from two original sets of three elements each?

combinatorics permutations

asked 1 hour ago Guest908764 1

1

vote

0

answers

11

views

Classifying irreducible modules

abstract-algebra representation-theory lie-algebras

asked 1 hour ago Joe Wolf 89

5

votes

0

answers

19

views

Can monics always be “made left-invertible” by adding arrows?

category-theory examples-counterexamples

asked 1 hour ago KJJ 51

1

vote

0

answers

15

views

Peter WInker's Mathematical Puzzle “Intervals and DIstances”

geometry solution-verification puzzle

asked 1 hour ago Tomasz Sternal 11

0

votes

0

answers

11

views

Is there such a thing as a reverse Menger Sponge / Carpet?

geometry fractals

modified 2 hours ago Xander Henderson 18.7k

0

votes

0

answers

10

views

Linear ODE and ZOH in control theory

ordinary-differential-equations dynamical-systems control-theory

asked 2 hours ago ofir_13 436

0

votes

1

answer

12

views

Number of submatrices from a given matrix

linear-algebra combinatorics matrices permutations

answered 2 hours ago Matthew Leingang 20.4k

0

votes

0

answers

9

views

Explaining in detail the contents of this question

functions discrete-mathematics

modified 2 hours ago Danilo Gregorin 993

0

votes

0

answers

8

views

Hitting time distributions for $M_t/M/\infty$ queues

probability-distributions markov-chains queueing-theory

asked 2 hours ago Muriel 59

1

vote

0

answers

11

views

How can i represent the terms of the following sequence?

sequences-and-series binomial-coefficients

asked 2 hours ago No-one Important 11

1

vote

0

answers

21

views

Examples and references of connections over elliptic curves

algebraic-geometry vector-bundles connections

modified 2 hours ago PerelMan 2,339

1

vote

0

answers

10

views

Is it a simplicial cone always a pointed cone?

discrete-mathematics linear-transformations convex-cone

modified 2 hours ago Angina Seng 129k

0

votes

0

answers

7

views

Question on proving that Haar functions form complete system

real-analysis functional-analysis

asked 2 hours ago Kate 83

3

votes

1

answer

34

views

If $N$ is the least normal subgroup of $AB$ containing $A$, then $(AB)/N \cong B$.

abstract-algebra group-theory solution-verification free-product

answered 2 hours ago vujazzman 1,238

1

vote

1

answer

37

views

Some Properties about the Characteristic of a Ring

abstract-algebra number-theory ring-theory ideals ring-homomorphism

modified 2 hours ago Servaes 41.6k

3

votes

1

answer

53

views

In non-euclidean geometry, can hypotenus of rightangle triangle be shorter than sides?

geometry soft-question recreational-mathematics spherical-geometry noneuclidean-geometry

modified 2 hours ago dohmatob 4,898

-1

votes

1

answer

23

views

Largest incircle given any point inside convex quadrilateral

algebra-precalculus circles plane-geometry quadrilateral

modified 2 hours ago Servaes 41.6k

2

votes

0

answers

18

views

A generalization of the theorem on natural irrationalities?

galois-theory separable-extension normal-extension

modified 2 hours ago SFeesh 381

0

votes

0

answers

32

views

Understanding a statement of a problem.

functional-analysis operator-theory normed-spaces

modified 2 hours ago DanielWainfleet 42.2k

2

votes

0

answers

14

views

Perron matrices

matrices eigenvalues-eigenvectors matrix-equations

asked 2 hours ago Manuela Silva 21

2

votes

0

answers

10

views

Strogatz Exercise 8.5.3: Logistic equation and Poincarè maps

ordinary-differential-equations nonlinear-system non-linear-dynamics

asked 2 hours ago user213575 21

1

vote

1

answer

24

views

Why is taylor expansion on function of discrete random variable “allowed”?

probability taylor-expansion

modified 2 hours ago Aaron Montgomery 7,225

2

votes

0

answers

12

views

Cover of an infinite group by multiplication of two cyclic subgroups

group-theory cyclic-groups normal-subgroups metabelian-groups

asked 2 hours ago Karen 531

0

votes

0

answers

32

views

A slightly weird topology/physics question

differential-topology physics

modified 2 hours ago Cloudy7 161

1

vote

0

answers

9

views

Embedd SU(n) into an enlarged twisted Spin(2n) in terms of Lie groups precisely

representation-theory manifolds lie-groups quotient-spaces homogeneous-spaces

modified 2 hours ago Bernard 145k

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