User Zzz

1 answers

20 votes

5k views

24 bookmarks

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

general-topology proof-verification

Nov 27 '15 at 10:36

2 answers

7 votes

4k views

4 bookmarks

Continuity of cartesian product of functions between topological spaces

Feb 26 '16 at 11:54

1 answers

5 votes

982 views

1 bookmarks

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

general-topology

Dec 3 '15 at 17:52

3 answers

4 votes

215 views

Last digit of $1238237^{18238456}$

elementary-number-theory

Jul 30 '15 at 18:14

1 answers

2 votes

1k views

1 bookmarks

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

abstract-algebra

Jul 29 '15 at 0:43

1 answers

2 votes

57 views

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

functional-analysis proof-verification

Jul 20 '16 at 18:45

0 answers

2 votes

116 views

1 bookmarks

Definition of extrema in calculus of variations

functional-analysis definition

Jun 26 '16 at 12:06

3 answers

2 votes

506 views

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

general-topology

Oct 30 '15 at 22:06

2 answers

1 votes

254 views

1 bookmarks

Continuous surjection from simple closed curve to unit circle

general-topology

Nov 21 '15 at 20:27

2 answers

1 votes

87 views

Formalize equivalence classes

logic first-order-logic

May 8 '17 at 7:31

0 answers

1 votes

65 views

2 bookmarks

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

multivariable-calculus taylor-expansion definition

Oct 3 '16 at 17:04

1 answers

1 votes

300 views

Definition of a neighborhood in normed linear space?

functional-analysis definition

Sep 26 '16 at 18:33

1 answers

1 votes

115 views

Euler-Lagrange example proof

functional-analysis proof-verification euler-lagrange-equation

Sep 4 '16 at 14:39

1 answers

1 votes

387 views

3 bookmarks

Calculus of variations and Bernstein's theorem

functional-analysis proof-explanation

Sep 1 '16 at 10:51

2 answers

1 votes

121 views

Incomplete subspace of Banach space

functional-analysis proof-writing

Aug 26 '16 at 14:23

1 answers

1 votes

108 views

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

general-topology

Mar 15 '16 at 17:45

4 answers

1 votes

225 views

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

general-topology

Mar 10 '16 at 20:23

1 answers

1 votes

159 views

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

general-topology proof-verification

Mar 10 '16 at 9:05

1 answers

1 votes

108 views

1 bookmarks

Define product topology for subspace

general-topology

Nov 26 '15 at 22:41

1 answers

0 votes

394 views

1 bookmarks

Calculus of variations and Euler's equation

functional-analysis proof-explanation

Sep 27 '16 at 10:56

1 answers

0 votes

319 views

2 bookmarks

Increment of a functional and Taylor's theorem

functional-analysis proof-explanation

Jun 30 '16 at 16:40

3 answers

0 votes

277 views

$(\omega +3)\cdot\omega=\omega\cdot\omega$

set-theory book-recommendation ordinals

Jun 8 '16 at 19:47

1 answers

0 votes

219 views

Generated subframe of a frame

logic modal-logic

Apr 22 '16 at 14:27

1 answers

0 votes

125 views

Find an equivalent standard translation for FO formula

logic proof-verification modal-logic

Apr 17 '16 at 17:27

1 answers

0 votes

244 views

1 bookmarks

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

logic modal-logic

Apr 15 '16 at 12:37

2 answers

0 votes

439 views

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

general-topology

Mar 15 '16 at 19:55

1 answers

0 votes

43 views

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

general-topology

Feb 23 '16 at 18:18

1 answers

0 votes

70 views

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

general-topology proof-verification

Feb 6 '16 at 18:45

1 answers

0 votes

52 views

1 bookmarks

How to define that in which hierarchy certain language belongs?

formal-languages

Feb 2 '16 at 18:22

1 answers

0 votes

3k views

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

formal-languages

Feb 1 '16 at 22:58

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