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Zzz
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20 votes
1 answer
6k 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

0 votes
1 answer
3k views

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

0 votes
2 answers
2k views

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

2 votes
1 answer
2k views

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

6 votes
1 answer
1k views

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

-2 votes
1 answer
655 views

Sierpinski space question

0 votes
2 answers
652 views

Open or closed mapping between closed disk and unit sphere

2 votes
3 answers
585 views

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

0 votes
2 answers
543 views

Quotient topology $\mathbb{R}/\sim $ where $x\sim y$ iff $x-y\in\mathbb{Z}$ [duplicate]

0 votes
1 answer
425 views

Calculus of variations and Euler's equation

1 vote
1 answer
423 views

Calculus of variations and Bernstein's theorem

0 votes
1 answer
378 views

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

0 votes
1 answer
354 views

Increment of a functional and Taylor's theorem

1 vote
1 answer
322 views

Definition of a neighborhood in normed linear space?

0 votes
2 answers
321 views

What does $A^{B}$ mean? [duplicate]

0 votes
3 answers
297 views

$(\omega +3)\cdot\omega=\omega\cdot\omega$ [duplicate]

1 vote
2 answers
275 views

Continuous surjection from simple closed curve to unit circle

0 votes
1 answer
253 views

Proof that standard translation of modal formula is equivalent to the FO formula

1 vote
4 answers
248 views

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

0 votes
1 answer
229 views

Generated subframe of a frame

4 votes
3 answers
225 views

Last digit of $1238237^{18238456}$

1 vote
1 answer
174 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
2 answers
128 views

Incomplete subspace of Banach space

0 votes
1 answer
127 views

Find an equivalent standard translation for FO formula

1 vote
1 answer
124 views

Define product topology for subspace

2 votes
0 answers
123 views

Definition of extrema in calculus of variations

1 vote
1 answer
118 views

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

1 vote
1 answer
115 views

Euler-Lagrange example proof

0 votes
0 answers
101 views

Sequence convergence in box topology