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Dec
6
answered Reals constructed from equivalence classes of Cauchy sequences of rationals.
Nov
30
answered Cardinality of set difference
Nov
28
comment Cancellation of Direct Product in Grp
How do you read $\times$-compact? "product compact"? Did you invent this definition?
Nov
25
comment $\Bbb{R}^2$ not homeomorphic to $\Bbb{R}^2\setminus \{0\}$
Your question was answered here: math.stackexchange.com/a/30888/5798
Nov
24
comment Circle to circle homotopic to the constant map?
Ah, great, I understand. I think I can write the proof. Thank you very much for your comment!
Nov
23
comment Circle to circle homotopic to the constant map?
To get the extension do you apply some generalisation to $\mathbb R^2$ of Tietze's extension theorem?
Nov
23
awarded  Popular Question
Nov
21
awarded  Popular Question
Nov
21
revised Let H be a proper subgroup of G of order prime $p^k$ and $N(H) = \{a \in G|aHa^{-1} = H\}.$Show that $N(H) \neq H.$
edited tags
Nov
21
revised Using Fourier analysis to show a function is positive
typos corrected
Nov
18
comment Open and closed complex sets
Or one of the real parts was meant to be imaginary?
Nov
18
answered Complex number isomorphic to certain $2\times 2$ matrices?
Nov
16
comment $\left\{\,f\in L^1[0,1]\,\big\vert\,\int_0^1\lvert f\rvert^2>1\right\}$ is open
Wouldn't it be easier to show that the closed unit ball is sequentially closed?
Nov
16
comment Does a continuous point-wise limit imply uniform convergence?
@IlmariKaronen Thank you for your comment! This is a great answer. I hope it gets some more upvotes.
Nov
16
comment Does a continuous point-wise limit imply uniform convergence?
Do I understand correctly: $f_n$ looks like a triangle getting smaller at the base? (piecewise linear function)
Nov
6
revised About $\infty$-norm on the space of convergent sequences
rolled back to a previous revision
Nov
6
revised About $\infty$-norm on the space of convergent sequences
added 1 character in body
Nov
5
comment Counterexample to the set of all algebraic polynomials being dense in $[0,1]$
I see. So I guess an algebraic polynomial is the same as a polynomial. : )
Nov
5
comment Counterexample to the set of all algebraic polynomials being dense in $[0,1]$
What is an algebraic polynomial?
Nov
5
answered Counterexample to the set of all algebraic polynomials being dense in $[0,1]$