Mathematics Stack Exchange

0

votes

1

answer

17

views

Number of compositions with sum N

combinatorics

answered 1 min ago JJ Hoo 49

0

votes

0

answers

2

views

Quadratic form over vector space $\mathbb{F}_q^d$

linear-algebra abstract-algebra combinatorics group-theory

asked 1 min ago ZFR 13.2k

3

votes

1

answer

29

views

Ideals of $\mathrm{End}_{k}(V)$

linear-algebra abstract-algebra ring-theory ideals

answered 4 mins ago Rene Schipperus 35.5k

0

votes

0

answers

6

views

Identifying the elements of the dihedral group of a hexagon from SageMath.

group-theory permutations sagemath

asked 5 mins ago Malcolm 43

2

votes

1

answer

75

views

nullity of a random matrix (infinite dimension) in $L^2$ space \begin{pmatrix} 1 & a & & \\ & 1 & a & \\ & & 1 & \dots\\ & & & \dots \end{pmatrix}

random-matrices infinite-matrices

modified 6 mins ago Jian 235

1

vote

1

answer

31

views

Functional equation with two inputs: $f(x,y)f(y,x)=1$

functional-equations

modified 12 mins ago Mohsen Shahriari 5,086

4

votes

0

answers

34

views

+50

If for every $x>0,P(|X_k|>x) \leq P(Y>x)$ then $\lim_k E[X_k|\mathcal{G}]=E[X|\mathcal{G}]$ a.s.?

probability-theory measure-theory conditional-expectation

modified 14 mins ago user 65

2

votes

0

answers

32

views

links between real and complex analysis

real-analysis complex-analysis functional-analysis philosophy

asked 15 mins ago H. Jenkins 123

0

votes

1

answer

9

views

Can we run ridge regression after variable selection by lasso

statistics regression

answered 15 mins ago Ryan 1,411

1

vote

0

answers

15

views

Prove that the sequence has a limit using only the definition of the limit

calculus sequences-and-series limits

asked 16 mins ago Matthew Ragdale 23

0

votes

2

answers

22

views

Rolling a dice and tossing a coin (Probability)

probability

answered 16 mins ago Snoop 4,444

1

vote

2

answers

17

views

Properties of Certain Random variables and sums of them

probability probability-distributions reference-request

answered 16 mins ago G Cab 31.9k

0

votes

1

answer

9

views

Work on a chain (applications of the integral)

calculus integration applications

answered 18 mins ago eng2math 38

3

votes

3

answers

54

views

Is there a slick argument to prove that, for $n>6$, $2(n-2)!=2^kk!(n-2k)! \implies k=1$?

combinatorics elementary-number-theory

modified 19 mins ago user 138k

0

votes

0

answers

13

views

How to check this linear functional is bounded or not?

real-analysis lp-spaces

modified 20 mins ago Sebastiano 4,515

1

vote

1

answer

36

views

Evaluation of the 'Odd Harmonic' Continued Fraction

continued-fractions

modified 27 mins ago Paul vdVeen 53

0

votes

1

answer

36

views

Cartesian formula for incenter of tangential quadrilateral from vertices only (no angles)

geometry

modified 28 mins ago Jean Marie 59.4k

1

vote

1

answer

21

views

Is there a simple functions between $2$ measurable functions?

measure-theory

answered 29 mins ago Steven Stadnicki 49.1k

0

votes

0

answers

21

views

Why does absolute convergence of a series imply the function is analytic?

sequences-and-series complex-analysis convergence-divergence

asked 29 mins ago Tariq 1,528

0

votes

0

answers

6

views

Proof that a sequence is a Markov Chain

probability stochastic-processes markov-chains

asked 30 mins ago Alejandro Zúñiga González 25

-1

votes

0

answers

16

views

Prove by induction in n, that sum.

solution-verification induction

asked 30 mins ago Jacob 1

0

votes

1

answer

45

views

Showing $\frac{2\sin\theta\cos i\phi}{2\cos\theta\sin i\phi}=\frac{\tan\theta}{i\tanh\phi}$

trigonometry hyperbolic-functions

modified 32 mins ago NickD 1,989

1

vote

2

answers

49

views

Find the partial fraction: $\frac{x^2}{(x-1)^2(x-2)^2(x-3)}$

algebra-precalculus self-learning partial-fractions

modified 33 mins ago Sebastiano 4,515

3

votes

1

answer

35

views

On the submodule of a direct sum of two modules

abstract-algebra modules examples-counterexamples

modified 33 mins ago Aryaman Maithani 12.9k

-1

votes

1

answer

18

views

Solve $x^3+px+q=0$ when $27q^2+4p^3<0$ using $\cos 3 \theta = 4\cos^3 \theta-3 \cos \theta$.

galois-theory cubic-equations

answered 33 mins ago Bernard 168k

1

vote

3

answers

35

views

Does the pointwise identity $\frac{e^{tf}-1}t\xrightarrow{t\to0+}f$ also hold with respect to the supremum norm?

real-analysis functional-analysis derivatives exponential-function

answered 36 mins ago Alex Ortiz 16.7k

2

votes

4

answers

1k

views

How many distinct trees with N nodes?

discrete-mathematics graph-theory trees

answered 36 mins ago warren w gremmel 1

0

votes

0

answers

13

views

Is there a standard definition of having an "advantage" in a game?

probability statistics game-theory

asked 36 mins ago Neel 185

1

vote

1

answer

32

views

Express $\int_0^1 x^{-x} \, dx$ as a series of constants $\sum_{n=1}^\infty a_n$

real-analysis integration sequences-and-series

modified 36 mins ago Arun Bharadwaj 612

-1

votes

0

answers

6

views

Probability Question Releated To Discrete Random Variables?

probability probability-theory probability-distributions

modified 39 mins ago HBKP 1

8

votes

1

answer

2k

views

Use the identity $\cos 3\theta = 4 \cos^3\theta- 3 \cos \theta$ to solve the cubic equation $t^3 + pt + q = 0$ when $p, q \in \mathbb{R}$.

galois-theory cubic-equations

answered 43 mins ago José Carlos Santos 363k

-1

votes

0

answers

4

views

Derive the asymptotic distribution with error term in heteroskedastic

statistics economics robust-statistics

asked 46 mins ago WayneSun 1

0

votes

0

answers

24

views

How do these properties of subsequences work?

real-analysis

asked 49 mins ago TreausreDragon 3

0

votes

0

answers

56

views

Prove the inequality by mathematical induction

real-analysis analysis inequality induction a.m.-g.m.-inequality

modified 49 mins ago Daniel Gendin 482

0

votes

1

answer

21

views

Radii of the new spheres if a sphere is cut into two parts.

analytic-geometry

answered 50 mins ago heropup 103k

2

votes

2

answers

53

views

Showing $\sum^\infty \frac{\log{(n^2 + 2)}}{n^2 + 1}$ converges

real-analysis calculus sequences-and-series convergence-divergence

answered 56 mins ago user 138k

1

vote

0

answers

19

views

Do the left and right "parts" of the matrix used when performing Gaussian Elimination have names?

terminology gaussian-elimination

modified 58 mins ago J. W. Tanner 56.8k

0

votes

1

answer

6

views

Measure of an increasing union

real-analysis measure-theory

answered 1 hour ago huj 183

0

votes

2

answers

15

views

Definition of a norm on a vector space of sequences

linear-algebra vector-spaces norm normed-spaces

answered 1 hour ago Mason 2,420

0

votes

1

answer

38

views

Deriving complex vector and scalar to satisfy this Householder transform equation

linear-algebra linear-transformations inner-products transformation

answered 1 hour ago Satan Lucifer 95

-1

votes

0

answers

9

views

How do I prove that permutation C is unequivocally given by C o A =B?

abstract-algebra permutations function-and-relation-composition

asked 1 hour ago passing_around 1

2

votes

1

answer

61

views

barycentric coordinates of the foot of an altitude in a tetrahedron

geometry triangles barycentric-coordinates

modified 1 hour ago Intelligenti pauca 39k

0

votes

0

answers

27

views

Logarithm of a non-diagonalizable matrix

matrices jordan-normal-form matrix-exponential

modified 1 hour ago AE_UTD 13

0

votes

0

answers

45

views

Given a degree-two endomorphism of an elliptic curve, how to construct the following map to $\Bbb P^1$?

algebraic-geometry elliptic-curves

modified 1 hour ago Hank Scorpio 1,284

1

vote

1

answer

19

views

Matrix representation of an operator in Non-Orthogonal bases

linear-algebra matrices vector-spaces operator-algebras quantum-mechanics

modified 1 hour ago Frederik vom Ende 1,907

0

votes

0

answers

19

views

Finding a function from its Jacobian (aske priorly but I don't understand the answer)

multivariable-calculus vectors matrix-calculus jacobian

asked 1 hour ago Makogan 2,011

0

votes

0

answers

16

views

For any pair of distinct real number sequences, is there always some algorithm that returns distinct integer sequences for each?

sequences-and-series functions algorithms computational-complexity

asked 1 hour ago virtuolie 39

-1

votes

0

answers

13

views

How can I find the probability of obtaining certain values of a sample that I drew from a population?

probability statistics

modified 1 hour ago d2nf9s8nbhy 1

0

votes

3

answers

29

views

Can this theorem be generalized to infinite dimensional vector spaces?

linear-algebra vector-spaces linear-transformations hamel-basis

answered 1 hour ago Stinking Bishop 12.9k

0

votes

0

answers

10

views

Existence of $\omega$-limit point of a dynamical system with an output?

real-analysis ordinary-differential-equations convergence-divergence dynamical-systems control-theory

asked 1 hour ago Norman 796

-1

votes

1

answer

26

views

To solve $z=(2+x)k$

algebra-precalculus

answered 1 hour ago chalbrak 1

1

vote

0

answers

16

views

Compute the dimensions of the vector spaces $\mathfrak m^n / \mathfrak m^{n+1}$.

abstract-algebra solution-verification

asked 1 hour ago pyon 1,271

0

votes

0

answers

20

views

How practical is it to test whether a particular number is polygonal?

elementary-number-theory algorithms polygons

asked 1 hour ago b1tth1ck 1

0

votes

0

answers

29

views

Do the poles of the $\Gamma(z)$ multiply out to 1 in some way?

complex-analysis gamma-function analytic-continuation

modified 1 hour ago Neptune 332

0

votes

0

answers

13

views

Estimate how many times to draw a score before going above a given limit

probability estimation

asked 1 hour ago Malin Edvardsen 1

3

votes

2

answers

34

views

Use class algebra to prove that if $A⊆B$ and $C=B−A$, then $A=B−C$.

elementary-set-theory

modified 1 hour ago Sebastiano 4,515

0

votes

0

answers

30

views

When minimum of two metric is again a metric

metric-spaces

modified 1 hour ago Sebastiano 4,515

0

votes

1

answer

13

views

Lower bound on rank of matrix with respect to eigen values

linear-algebra matrices eigenvalues-eigenvectors matrix-rank

answered 2 hours ago Mason 2,420

1

vote

0

answers

20

views

Natural deduction, beginning premises

derivatives proof-writing proof-explanation computer-science natural-deduction

modified 2 hours ago Sebastiano 4,515

1

vote

0

answers

9

views

Show that the distinguished logarithm of a probability measure is subadditive

real-analysis complex-analysis probability-theory measure-theory exponential-function

asked 2 hours ago 0xbadf00d 12.1k

1

vote

1

answer

21

views

Is a surjective morphism $V \to U$ quasi-compact and quasi-separated, if $V, U$ are quasi-compact and $U$ is affine?

algebraic-geometry descent

answered 2 hours ago leoli1 8,152

10

votes

1

answer

85

views

Is every square matrix a sum of a diagonal matrix and a nilpotent matrix

linear-algebra matrices

answered 2 hours ago levap 60.1k

0

votes

0

answers

12

views

Non trivial solution of a linear homogeneous system with singular matrix.

linear-algebra matrices systems-of-equations determinant

modified 2 hours ago Feynman_00 255

-1

votes

1

answer

19

views

number of m by n echelon matrices made with members of a finite field of characteristic q

linear-algebra matrices

answered 2 hours ago Amirsalar Safaei 1

2

votes

0

answers

18

views

The process of complex integration is the same as that of real integration

complex-integration

asked 2 hours ago johnbear02 23

0

votes

1

answer

19

views

What bounds does an approximate identity give in terms of supremum's of functions?

analysis fourier-analysis harmonic-analysis

answered 2 hours ago Funktorality 2,841

2

votes

1

answer

13

views

How to constrain second order cone program so vector elements are either x or zero?

optimization convex-optimization constraints

answered 2 hours ago Mark L. Stone 3,858

1

vote

1

answer

47

views

Prove complete graph $K_n$ can be decomposed into $\lceil n/2 \rceil$ paths or $\lfloor n/2\rfloor$ cycles when $n$ is odd.

graph-theory

modified 2 hours ago Misha Lavrov 98.1k

2

votes

1

answer

37

views

How to show that the cokernel of $\mathbb{Z}[x]^2\to\mathbb{Z}[x]^2$ given by $A=\begin{pmatrix}2 & x \\ 0 & 0\end{pmatrix}$ isn't a sum of cyclics?

abstract-algebra polynomials ring-theory modules

modified 2 hours ago user26857 46k

0

votes

0

answers

7

views

Strongly convex function related inequality

convex-analysis convex-optimization

asked 2 hours ago E.J. 821

1

vote

1

answer

47

views

Is $f(p)=\beta p^{\alpha}$ the unique nonnegative function on $[0,1]$ satisfying $\frac{f(p)}{f(1-p)}=\left(\frac{p}{1-p}\right)^{\alpha}$?

real-analysis analysis

modified 2 hours ago Mohsen Shahriari 5,086

2

votes

0

answers

49

views

Count different monomials up to a permutation of variables in a generating function

combinatorics graph-theory permutations generating-functions multivariate-polynomial

modified 2 hours ago BillyJoe 1,311

0

votes

0

answers

21

views

Difference between limit point, accumulation point, etc.

general-topology

modified 2 hours ago MJD 60.6k

0

votes

1

answer

47

views

To check proposition of Self-referential sentence

logic paradoxes

answered 2 hours ago mohottnad 745

0

votes

0

answers

6

views

Optimization with positive definite constraints

optimization convex-optimization positive-definite constraints

asked 2 hours ago Tan 417

1

vote

0

answers

32

views

When is a de Rham cohomology class the Poincaré dual of the fundamental class of a closed submanifold?

algebraic-topology complex-geometry

modified 2 hours ago Michael Albanese 85k

0

votes

0

answers

8

views

Limiting density for sequence of points

measure-theory probability-distributions

asked 2 hours ago thedude 1,575

0

votes

0

answers

3

views

Surface order large deviation in Ising ferromagnet

statistical-mechanics concentration-of-measure large-deviation-theory gibbs-measure

asked 2 hours ago anurag anshu 347

0

votes

0

answers

15

views

For set notation such as D={a1xa2:a1,a2∈A}, do a1 and a2 have to be distinct?

elementary-set-theory

modified 2 hours ago Mauro ALLEGRANZA 87.2k

-1

votes

0

answers

8

views

Obtaining an "approximate but reduced version of a matrix"

linear-algebra matrices matrix-rank svd

asked 3 hours ago Michael Black 1

0

votes

1

answer

12

views

Partition function of multi-particle canonical ensemble

physics integer-partitions

answered 3 hours ago Andrei 28.6k

0

votes

1

answer

18

views

A sequence of cutoff functions

functional-analysis analysis multivariable-calculus partial-differential-equations regularity-theory-of-pdes

modified 3 hours ago Mathguide 189

0

votes

0

answers

6

views

Cycle Index tables and a way to obtain $Z_m(S_p)$?

permutations symmetric-groups permutation-cycles

asked 3 hours ago Baklava Gain 443

3

votes

0

answers

66

views

Alternate proof of a Hadamard Gamma sum:$\sum\limits_{-\infty}^0 \text H(x)= \frac{\text{Ei}(2)-\text{Ei}(1)}{e} $

sequences-and-series special-functions alternative-proof gamma-function harmonic-numbers

modified 3 hours ago Tyma Gaidash 3,319

2

votes

1

answer

71

views

Olympiad functional equations proof verification: $f\bigl(2f(x)+f(y)\bigr)=2x+y$ on $\mathbb Q$ and $f\bigl(xf(x)+f(y)\bigr)=f(x)^2+y$ on $\mathbb R$

solution-verification proof-explanation contest-math functional-equations

modified 3 hours ago Mohsen Shahriari 5,086

0

votes

0

answers

11

views

Regular perturbation on Fredholm equation

taylor-expansion approximation integral-equations perturbation-theory

asked 3 hours ago Harry_A 1

1

vote

1

answer

85

views

+50

Is there a way to write the $n^\text{th}$ super root in terms of the lambert W function?

inverse-function lambert-w tetration

modified 3 hours ago Tyma Gaidash 3,319

1

vote

0

answers

13

views

Newton's Shell Theorem in non-Euclidean spaces

integration noneuclidean-geometry

asked 3 hours ago Logan R. Kearsley 365

0

votes

0

answers

11

views

Practical advice for setting Lagrange Multipliers for an optimization problem with positivity and range constraints

optimization numerical-methods convex-optimization lagrange-multiplier

asked 3 hours ago krishnab 1,373

1

vote

2

answers

48

views

Distribution of dot product of random vectors drawn from $\mathbb{N}^n$

probability expected-value variance

modified 3 hours ago d.k.o. 22.9k

0

votes

0

answers

19

views

Exercise regarding null space and $\ell_1$ norms

linear-algebra

asked 3 hours ago asdf 329

4

votes

0

answers

47

views

+200

Comparing "local compactness numbers" of two strong logics

logic set-theory model-theory higher-order-logic

modified 4 hours ago Noah Schweber 208k

0

votes

0

answers

11

views

Trouble generalising the concept of complementary functions from second-order ODEs to $n$-th order ODEs

calculus ordinary-differential-equations

asked 4 hours ago javan.g 23

0

votes

1

answer

24

views

Continuous partial derivative for non differentiable funcion

multivariable-calculus continuity partial-derivative

modified 4 hours ago Bernard 168k

2

votes

1

answer

28

views

Isosceles triangles with integer side lengths whose vertices are lattice points

geometry

modified 4 hours ago Somos 28k

4

votes

0

answers

22

views

How do spheres curve in hyperbolic space?

hyperbolic-geometry spherical-geometry

asked 5 hours ago Logan R. Kearsley 365

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