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visits member for 2 years, 8 months
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Aug
2
answered Video lectures of algebraic geometry (Hartshorne, Shafarevich, … )
Aug
2
comment What is the smallest number x such that $180\times x$ is a perfect cube?
I wonder if "zero" is an appropriate answer?
Aug
2
comment Video lectures of algebraic geometry (Hartshorne, Shafarevich, … )
Are you interested in courses not in English?
Jul
19
comment Coin flip gamble
Try this en.wikipedia.org/wiki/St._Petersburg_paradox
Jul
2
awarded  Curious
May
30
comment $f$ is continuous and $f(V)$ is open whenever $V$ is open $\implies$ $f$ is monotone
This will help wj32.org/wp/2013/01/15/…
May
27
awarded  Nice Answer
May
27
comment Covering one square by three smaller squares
Generalization and proper explanation mathoverflow.net/questions/49674/…
May
27
comment Difficult inequality, difficult solution, but how to prove?
I suppose, your first root (with $\sqrt{249}$) isn't correct. It is the root for $x^3-x^2+x-2$, not for $x^3-x^2-2x-3$.
May
27
revised Difficult inequality, difficult solution, but how to prove?
LaTeX changes
May
27
suggested suggested edit on Difficult inequality, difficult solution, but how to prove?
May
27
awarded  Fanatic
May
26
answered Statements with rare counter-examples
May
1
comment Prove that $f(x) = 4 - 15x$ is continuous
This is the proof for point $c$. For your function you may let $c$ be any (your function is obviously continuous ay every point at all), but if you want continuity at $0$ you may just replace $c$ with $0$ everywhere.
May
1
comment Prove by induction that $\;A^n = PD^nP^{-1}$
What are these $A$, $D$? Nevertheless, if you can prove it for $n=1$ you should do it and additionally prove that if your statement is true for some $n$ (you don't need to prove this fact itself) then it is indeed true for $n+1$.
May
1
revised Prove that $f(x) = 4 - 15x$ is continuous
added 12 characters in body
May
1
answered Prove that $f(x) = 4 - 15x$ is continuous
May
1
revised Formal proof of famous theorem
added 1 character in body
May
1
comment Formal proof of famous theorem
I want examples of formal proofs. Let it be "lists". And I've provided an example which uses first-order predicate calculus. I'm quite sure, it is a formal system.
May
1
asked Formal proof of famous theorem