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Yerbolat's user avatar
Yerbolat
  • Member for 7 years, 11 months
  • Last seen more than a month ago
5 votes
2 answers
309 views

Does an equivalence relation on a group play well with the group operation, provided that the equivalence class of the identity is a normal subgroup?

4 votes
1 answer
219 views

A simple proof for: An open set in $\mathbb{R}$ is a countable union of open intervals

3 votes
1 answer
100 views

Is the set a group if left translations form a group?

2 votes
0 answers
147 views

Definition of the derivative of a real function in "Baby Rudin"

2 votes
0 answers
115 views

A presentation of a Dihedral group

2 votes
1 answer
925 views

Relative boundary of $A$ in $V \subset \mathbf{R}^n$

1 vote
1 answer
3k views

Necessary and sufficient conditions for the convergence of a series

1 vote
1 answer
97 views

A motivation for the definition of the inverse image of $E\subset Y$ under a mapping $f:X\to Y$

1 vote
1 answer
361 views

Every linearly ordered subset $\mathcal{A}$ of a set $\mathcal{W}$ of well orderings $\leq$ on subsets of some set $X$ has an upper bound.

1 vote
2 answers
599 views

Real Analysis Folland Proposition 1.5

0 votes
1 answer
116 views

Best Fit Line Slope

-4 votes
3 answers
229 views

Isomorphism between $D_3$ and $S_3$ [closed]