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ensbana
  • Member for 8 years, 9 months
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6 votes
1 answer
430 views

Multiplying both sides of an equation in proofs

6 votes
3 answers
6k views

Addition and Multiplication in $F_4$ [duplicate]

6 votes
2 answers
151 views

Group action on topological spaces.

6 votes
1 answer
154 views

In van Kampen’s theorem, what happens to the loops not in $\pi_1(U_\alpha \cap U_\beta)$?

5 votes
1 answer
728 views

Quotient of the torus being homeomorphic to Mobius strip?

5 votes
3 answers
735 views

Product of two polytopes is a polytope

4 votes
1 answer
106 views

Definitions of pyramid (eg, tetrahedron as "$1$-fold $3$-pyramid" vs "$3$-fold pyramid")

4 votes
2 answers
463 views

Help understanding how a topological cone is constructed.

4 votes
1 answer
97 views

Question about the definition of homotopy equivalence

4 votes
1 answer
442 views

Show that the functor $\pi_0:$ TOP $\to$ SET that takes the path components of topological spaces does not preserve pushouts.

4 votes
1 answer
142 views

Why is Furch's "knotted hole ball" not shellable?

4 votes
0 answers
520 views

Proof that singleton sets are Borel sets in $\Omega = (0,1]$.

4 votes
2 answers
120 views

Why is the direct product of two groups $G_1 \times G_2$ too small to be their coproduct?

4 votes
1 answer
90 views

Confusion about definition of faithful group action.

4 votes
1 answer
50 views

Some probabilistic reasoning in graphs.

4 votes
1 answer
105 views

Injection between posets $(\Phi([-1,1]^d)\setminus\{\emptyset\},\subseteq)$ and $(\{-, 0,+\}^d,\preceq)$, where $-\preceq 0$ and $+\preceq 0$.

4 votes
0 answers
76 views

Upper bound of number of triangles in an edge-colored graph, given that none of the triangles are rainbow.

3 votes
1 answer
55 views

Show that the saturation number sat$(7,C_4) > 7$.

3 votes
0 answers
64 views

Show that if a space $X$ is not path-connected, then the suspension $\Sigma X$ is not simply connected.

3 votes
1 answer
273 views

Starting the simplex method from a given basic feasible solution?

3 votes
0 answers
38 views

How to visualize and explain complicated 3-dimensional structures?

3 votes
2 answers
70 views

How does the size of a topology affect the continuity of maps?

3 votes
2 answers
96 views

Openness/Closeness of components of the topologist's sine curve

3 votes
1 answer
429 views

Coloring $\mathbb{N}$ with finitely many colors results in monochromatic $x,y,z \in \mathbb{N}$ such that $x+y = z$.

3 votes
3 answers
87 views

Recurrence of $\{0,1,2\}^n$ tuples that don't contain $2$ followed immediately by $0$

3 votes
3 answers
103 views

Linear Independence in polynomial space.

3 votes
3 answers
339 views

Prove that a metric space in which every infinite subset has a limit point is separable.

3 votes
3 answers
309 views

Why do the coefficients of a equation, expressed in terms of a small parameter epsilon, have to be 0?

3 votes
1 answer
416 views

Schlegel diagram and d-diagram

3 votes
0 answers
210 views

Relationship between Affine Dependence and Linear Dependence in Oriented Matroids?

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