List questions from examples-counterexamples

Published on 12 Apr 2026 - 22:05

112

Views

Is $X$ pseudocompact

Published on 11 Apr 2026 - 10:57

923

Views

How to directly show that Figure 8 injective immersion is not a monomorphism

Published on 13 Apr 2026 - 2:58

285

Views

Sufficient condition for irreducibility of polynomial $f(x,y)$

Published on 12 Apr 2026 - 8:14

93

Views

Sufficient condition for reducibility of polynomial $f(x,y)$

Published on 13 Apr 2026 - 10:15

395

Views

Looking for example of an order homomorphism that doesn't preserve joins.

Published on 13 Apr 2026 - 10:57

351

Views

Regular $T_2$ space which is not completely regular.

Published on 13 Apr 2026 - 6:40

115

Views

If $f: \mathbb{C}\to\mathbb{C}$ is bounded, then is it a constant?

Published on 13 Apr 2026 - 12:55

201

Views

For every monoid $M$ with zero is there a group $G$ such that $\mathrm{Grp}(G,G)\cong M$?

Published on 27 Mar 2026 - 18:02

176

Views

Real commutative Banach algebra with identity

Published on 10 Apr 2026 - 22:50

792

Views

A semisimple commutative Banach algebra with a non-semisimple quotient

Published on 30 Mar 2026 - 5:31

196

Views

Are all norms equivalent on a (non-semisimple) commutative Banach algebra?

Published on 30 Mar 2026 - 5:32

1.8k

Views

Counterexample to inverse Leibniz alternating series test

Published on 11 Apr 2026 - 2:20

1.9k

Views

Does a monotone function on an arbitrary subset of $\mathbb R$ always have at most countable number of discontinuity?

Published on 13 Apr 2026 - 5:51

368

Views

Interesting Problems for NonMath Majors

Published on 11 Apr 2026 - 12:46

List Question

A completely regular topological space which is $T_0$ but not $T_1$?

Is $X$ pseudocompact

How to directly show that Figure 8 injective immersion is not a monomorphism

Sufficient condition for irreducibility of polynomial $f(x,y)$

Sufficient condition for reducibility of polynomial $f(x,y)$

Looking for example of an order homomorphism that doesn't preserve joins.

Regular $T_2$ space which is not completely regular.

If $f: \mathbb{C}\to\mathbb{C}$ is bounded, then is it a constant?

For every monoid $M$ with zero is there a group $G$ such that $\mathrm{Grp}(G,G)\cong M$?

Real commutative Banach algebra with identity

A semisimple commutative Banach algebra with a non-semisimple quotient

Are all norms equivalent on a (non-semisimple) commutative Banach algebra?

Counterexample to inverse Leibniz alternating series test

Does a monotone function on an arbitrary subset of $\mathbb R$ always have at most countable number of discontinuity?

Interesting Problems for NonMath Majors

Trending Questions

Popular # Hahtags

Popular Questions