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0 votes
0 answers
5 views

Nonexistence of the function f on $[0,1]\times [0,1]$

0 votes
1 answer
751 views

Summary of different Fourier Transforms / Fourier Series

3 votes
2 answers
100 views

When/why is substitution valid for equations?

11 votes
5 answers
1k views

How can the golden ratio secretly appear as a root of a sixth-degree polynomial?

1 vote
2 answers
73 views

Solve the equation $x^{\sqrt[n]{x}} = a^{(n-x)\sqrt[n]{x}+a}$.

0 votes
0 answers
14 views

Free monoids satisfying $x^r=x$ for all $x$

2 votes
0 answers
66 views
+100

Is the Quotient of Two Coprime Polynomials in $\mathbb{R}[x,y]$ With Isolated Zeroes at the Origin Ever $C^\infty$?

1 vote
0 answers
87 views

Mistake in the proof of Orientation Reversal

4 votes
3 answers
348 views

Confused About Vector Spaces

3 votes
1 answer
36 views

Comparison of ideal operations in PIDs and in commutative rings (gcd, lcm)

0 votes
3 answers
278 views

Show that $f(x) = x^{{1}/{3}}$ is Hölder on $\mathbb{R}$

0 votes
0 answers
13 views

Steady states in a Markov chain, how to understand the method of obtaining them in terms of linear algebra?

5 votes
2 answers
123 views

Does $(\{(p/q)^n\})_{n\in\mathbb{N}}$ have infinitely many accumulation points

2 votes
1 answer
96 views

Inverse of the matrix ${\bf B}^2 - {\bf A}^* {\bf A}$

0 votes
1 answer
732 views

Equilibrium point of a linear second order equation with constants

6 votes
3 answers
199 views

Continuous group actions

2 votes
0 answers
107 views

How to solve for boundaries of Julia Sets?

9 votes
2 answers
4k views

How to compute a negative "Multibrot" set?

0 votes
0 answers
16 views

Regarding computing singular values using covariance matrix as opposed to using SVD

2 votes
6 answers
144 views

Let $A$ and $B$ be two nonempty bounded subsets of $\mathbb{R}$. Prove $\sup B \leq \sup A$.

3 votes
0 answers
34 views

Can two nonconstant polynomials with integer coefficients never be simultaneously non-squarefree at all sufficiently large $n$?

2 votes
2 answers
741 views

Test symmetricity for a sparse matrix

7 votes
2 answers
192 views
+200

Are the constant functions in $\mathcal C (X, \mathbb R)$ first-order definable?

7 votes
0 answers
83 views

The cotangent bundle is almost a comonad. How to fix that?

2 votes
0 answers
29 views

Why two real smooth conics cannot be tangent at non-real finite points, in contrast with cubic–circle examples

5 votes
2 answers
85 views

If $L/K$ is purely inseparable and $M/K$ is arbitrary, then $|\mathrm{Spec}(L \otimes_K M)| = 1$

0 votes
2 answers
769 views

Step size for numerical methods.

4 votes
1 answer
740 views

Representing elements in homology of a surface by embedded curves

1 vote
1 answer
79 views

The geometry of $ 2^2 = \left(y+\frac{1}{y}\right)^2 - \left(y-\frac{1}{y}\right)^2 $

3 votes
1 answer
30 views

Uniqueness of the Smooth Manifold Chart Lemma of J. M. Lee's Introduction to Smooth Manifolds

9 votes
1 answer
8k views

Harvard Math 55 materials

2 votes
1 answer
39 views

Let $d(x)$ be the number of divisors of natural number x. Find the solution set of the equation $n | d(n)d(n+1)d(n+2)$

-1 votes
0 answers
31 views

Domain and Range with Linear Inequalities in Desmos

3 votes
0 answers
19 views

A method to construct irreducible polynomials whose second iterate is reducible?

3 votes
2 answers
1k views

Lebesgue measure of a subspace of lower dimension

2 votes
3 answers
158 views

Does this $2$-dimensional difference equation have a closed-form solution?

0 votes
1 answer
18 views

Inverse of Dirichlet autoconvolution

0 votes
1 answer
746 views

Double sigma summation is in complexity calculation

1 vote
1 answer
73 views

Decomposition $PLUP^{-1}$

1 vote
0 answers
27 views

Is it correct that $\cos(t) + \varepsilon_t$ is not a stationary process? What’s the intuition behind it?

7 votes
0 answers
107 views

Simulating the results of a differential equation

0 votes
0 answers
29 views

Sequential Numerical Integrals

1 vote
0 answers
85 views

Function fields over finite field.

0 votes
0 answers
58 views

What is the area of the set of points with escape count $n$ in a generic Burning Ship fractal?

9 votes
2 answers
234 views

Seeking analytic proof for $\sum_{n=r}^\infty \frac1{n!}{n-1\brack r-1} = 1$

-1 votes
1 answer
98 views

Is the $\mathrm dx$ really necessary for definite integrals?

2 votes
1 answer
86 views

Most Important Asymmetric Computational Problems in Mathematics and Beyond.

3 votes
2 answers
136 views
+50

A solution for $A-A=\mathbb{Q}\setminus \{\pm1,\pm 2,\cdots,\pm m\}$

0 votes
3 answers
773 views

Finding the Lagrangian of a particle of mass $m$ sliding along a parabola

1 vote
0 answers
11 views

Explicit formula for Hopf map onto complex projection space $\mathbb{C}P^k$?

0 votes
0 answers
5 views

Post critical points with every preimage critical or post-critical

1 vote
0 answers
31 views

Differential of the identity function between $\mathbb R$ with distinct differential structures

1 vote
0 answers
30 views

Prove inequality $\frac{3}{x+y+z} \ge \frac{2}{xy+yz+zx} + \frac{1}{x^2+y^2+z^2}$ given $\sum \frac{1}{x+y} = \frac{3}{2}$

6 votes
3 answers
1k views

What is the closed form approximation of the asymptotic growth rate of the superfactorial function?

4 votes
2 answers
904 views

On what interval does it converge absolutely, uniformly,fail to converge uniformly?

0 votes
1 answer
739 views

Let $ABCD$ be a convex quadrilateral with $AD = BC$ and $∠A + ∠B = 120°$ . Prove triangle formed by midpoints of $CD$, $AC$ and $BD$ is equilateral.

2 votes
2 answers
948 views

Is the Russell paradox formalizable in type theories?

0 votes
1 answer
66 views

Showing positive definite quadratic forms give the "most symmetrical" metrics over $\mathbb{R}^n$

1 vote
1 answer
3k views

Why do two vector fields commute iff their flows do?

0 votes
1 answer
243 views

TSP on a subset of a graph

0 votes
1 answer
1k views

Inverse Laplace Transform With Dead Time

9 votes
2 answers
882 views

Prerequisites for understanding Borel determinacy

0 votes
0 answers
41 views

Using Banach-Tarski to disprove the existence of a volume function in $\mathbb{R}^3$

0 votes
0 answers
18 views

ECM vs. QS (Elliptic Curve Method vs. Quadratic Sieve)

9 votes
4 answers
3k views

Justification for the substitution method of indefinite integration

0 votes
1 answer
57 views

When is $\sum_{i = 0}^n (-1)^i\binom{A}{i}\binom{B}{n-i} \neq 0$?

1 vote
2 answers
803 views

Orthogonal projection matrix $P$ onto the range of a $3 \times 2$ matrix

1 vote
0 answers
26 views

The median of a frequency distribution and $g(x)=\sum_{k=1}^n f_k |x-x_k|$

3 votes
3 answers
818 views

Spanning set and Subset

1 vote
0 answers
31 views

Intersection of A-excircle and circumcirlce

1 vote
0 answers
41 views

Maximum Value of a Fractional Quadratic Form over the Complex Unit Sphere with Projection Constraint

13 votes
1 answer
712 views

Challenging identity regarding Bell polynomials

10 votes
2 answers
1k views

Polylogarithms of negative integer order

1 vote
0 answers
59 views

Derivative of $e^{Qt}$ (when $Q$ is a matrix)?

2 votes
0 answers
67 views

Consistency of the notions of internal logic/language of a topos

3 votes
1 answer
748 views

Changing a simplex grid to an orthogonal grid.

5 votes
3 answers
137 views

Remote generation of functions

0 votes
1 answer
39 views

Is every nilpotent element of a ring, a clean element

3 votes
0 answers
36 views

Find the least $n$ such that $n^{n}$ does not divide $1_{2}\times12_{3}\times123_{4}\times\cdots\times(1:2:3:\cdots:2025)_{2026}$

0 votes
1 answer
60 views

How to check the integral inequality appearing in Boltz Problem

2 votes
0 answers
27 views

Are there butcher tables for adaptive embedded runge kutta 12(10) methods that DON'T use the second order formulation?

6 votes
0 answers
119 views

On conditions for $\lvert R/(I+J)\rvert \ge \lvert I\cap J/IJ\rvert$

16 votes
2 answers
3k views

Book recommendations for commutative algebra and algebraic number theory

2 votes
0 answers
45 views

A cohomological proof that $\mathbb{R}$ has Property (T)--- what is wrong?

1 vote
0 answers
60 views

When does the inverse of a sequence of matrices converge entrywise?

0 votes
2 answers
769 views

Show that the recursion $f(n) = 2f(n-1) + f(n-2)$ for $n \ge 2$ and $f(0) = 1, f(1) = 3$ is true.

4 votes
1 answer
46 views

Showing that under certain conditions every cogenerator is a generator.

0 votes
1 answer
907 views

Find continued fractions and corresponding rationals

8 votes
1 answer
73 views

Truncated functions converging to zero weakly imply that the function is zero?

0 votes
1 answer
79 views

For any square matrix $A \in M_{n \times n}(\mathbb{R}), \ker(A) \subseteq \ker(A^2)$

0 votes
0 answers
25 views

Condition for exact equation, explaining and derivation

63 votes
9 answers
32k views

If $a^3 =a$ for all $a$ in a ring $R$, then $R$ is commutative.

4 votes
2 answers
74 views

Some tricks about locus problem

3 votes
1 answer
59 views

A gentle Course in Local Class Field Theory, Proof of Corollary 12.6

1 vote
0 answers
53 views

Does this commutative ring $R$ capture all terminating programs?

7 votes
0 answers
77 views

Critical points of a cubic function with two unit-circle roots

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