Forever Mozart's user avatar
Forever Mozart's user avatar
Forever Mozart's user avatar
Forever Mozart
  • Member for 12 years, 2 months
  • Last seen more than 4 years ago
  • Paris, Texas
61 votes
5 answers
38k views

When is the closure of an intersection equal to the intersection of closures?

30 votes
5 answers
7k views

Is the Cantor set made of interval endpoints?

19 votes
0 answers
652 views

Exercise in Engelking's book regarding a disconnected space.

19 votes
1 answer
1k views

Is the graph of the Conway base 13 function connected?

17 votes
2 answers
932 views

Cantor set minus endpoints homeomorphic to irrationals?

13 votes
1 answer
662 views

Property between totally disconnected and zero dimensional

12 votes
2 answers
447 views

Equivalence relation on a continuum

11 votes
1 answer
442 views

Cantor set with pairs of points identified

10 votes
2 answers
522 views

Martin's Axiom and Choice principles

9 votes
2 answers
1k views

Relationships between AC, Ultrafilter Lemma/BPIT, Non-measurable sets

9 votes
5 answers
1k views

Identities similar to $\arctan(x)+\arctan(1/x)=\pi/2$

8 votes
1 answer
212 views

The Hahn-Mazurkiewicz Theorem for non-metric spaces

8 votes
10 answers
4k views

Good final exam bonus problem for calculus students? [closed]

8 votes
0 answers
314 views

Is $X\simeq [0,1]$?

8 votes
1 answer
937 views

Does a compact connected complete linear order have the fixed point property?

8 votes
1 answer
886 views

Totally disconnected vs. totally separated.

7 votes
1 answer
142 views

In $ \mathsf{ZFC} $, is it true that $ \text{cf}(\kappa) < \text{cf}(2^{\kappa}) $ for all cardinals $ \kappa $?

7 votes
1 answer
466 views

Continuous surjective functions $\omega_1 \to \omega_1$.

7 votes
2 answers
284 views

Countable number of arcs between two intervals

6 votes
1 answer
235 views

Is the closure of a discrete subspace of $[0,1]$ necessarily countable?

6 votes
1 answer
222 views

Integral of difference of sin functions squared is $2\pi$?

6 votes
2 answers
845 views

Does a symmetric matrix with all entries $0$ or $1$ and with diagonal $0$ have integer eigenvalues?

5 votes
2 answers
70 views

How many limits of limits are there in $\omega_1$?

5 votes
1 answer
53 views

Topological property: set-theoretically large subsets of an infinite space are not compact.

5 votes
1 answer
426 views

Is every countable regular space zero-dimensional?

5 votes
1 answer
137 views

Homeomorphisms which switch 2 points

5 votes
1 answer
151 views

Connected topology on $\mathbb Q$ such that every point is a cut point?

5 votes
0 answers
78 views

Limiting the size of near-coherence classes in $\omega^*$

4 votes
1 answer
141 views

Is $\mathbb R$ connected if we make the rationals open?

4 votes
1 answer
1k views

Friendship theorem: need help with part of proof.

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