user avatar
user avatar
user avatar
Zzz
  • Member for 7 years
  • Last seen more than 4 years ago
20 votes
1 answer
5k views

Proof that product topology of subspace is same as induced product topology

7 votes
2 answers
4k views

Continuity of cartesian product of functions between topological spaces

6 votes
1 answer
1k views

Product space that is compact, but isn't sequentially compact

4 votes
3 answers
224 views

Last digit of $1238237^{18238456}$

2 votes
1 answer
2k views

If $\gcd(a,b)=1$, then there exists integers $x$ and $y$ such that $xa + yb = 1$

2 votes
3 answers
571 views

If $X$ is compact metric space, then $X$ is bounded

2 votes
1 answer
60 views

Prove that norm $\| y \|=\sqrt{\int_{a}^{b}| y(x)|^2 dx}$ forms a linear space

2 votes
0 answers
122 views

Definition of extrema in calculus of variations

1 vote
0 answers
66 views

Taylor's theorem for function F(x,y,z)

1 vote
2 answers
89 views

Formalize equivalence classes [closed]

1 vote
2 answers
125 views

Incomplete subspace of Banach space

1 vote
1 answer
418 views

Calculus of variations and Bernstein's theorem

1 vote
1 answer
115 views

Euler-Lagrange example proof

1 vote
1 answer
319 views

Definition of a neighborhood in normed linear space?

1 vote
1 answer
172 views

If $E\subseteq X$ is connected, $E\cap A\neq\emptyset$ and $E\cap(X\setminus A)\neq\emptyset$ then $E\cap\partial A\neq\emptyset$

1 vote
4 answers
241 views

Every half-plane $H=\{(x,y)\in\mathbb{R}^{2}\mid ax+by+c\geq 0\}$ is connected

1 vote
1 answer
116 views

Homeomorphism between $X/\tilde~$ and $Y/\tilde~'$

1 vote
2 answers
271 views

Continuous surjection from simple closed curve to unit circle

1 vote
1 answer
123 views

Define product topology for subspace

0 votes
2 answers
2k views

What are open subsets of half-open interval of $\mathbb{R}$?

0 votes
0 answers
101 views

Sequence convergence in box topology

0 votes
2 answers
57 views

Equivalance classes example

0 votes
1 answer
3k views

Is epsilon a useless symbol and when epsilon does belong into CFL?

0 votes
1 answer
53 views

How to define that in which hierarchy certain language belongs?

0 votes
1 answer
73 views

Proof that $\{\,\left]a,\infty\right [\mid a\in\mathbb{R}\,\}\cup\{\mathbb{R} \}\cup\{\emptyset \}$ is topology of $\mathbb{R}$

0 votes
1 answer
43 views

$G=U\cap F$, where $U\subseteq X$ is closed, iff $G\subseteq F$ closed in $X$

0 votes
1 answer
78 views

Validity at state w

0 votes
1 answer
374 views

$f$ is homeomorphism iff $A\subseteq X$ open iff $f(A)\subseteq Y$ is open

0 votes
1 answer
88 views

Open map from $\mathbb{R}$ to Sierpinski space

0 votes
2 answers
640 views

Open or closed mapping between closed disk and unit sphere