435 reputation
513
bio website in.another.dimension
location Athens, Greece
age 46
visits member for 3 years, 10 months
seen 2 days ago

Interests: math, programming and games, not necessarily in that order.

Favourite numbers: Surreals


Dec
18
comment Does this algorithm find prime numbers only?
" for verifying that 147 is prime, ..."? The wording does not look appropriate, considering that 147 is not prime.
Dec
13
comment Trisecting an angle
and another +1 for the conclusion that you must have made a mistake.
Dec
13
comment Trisecting an angle
An initial 135 degrees angle would also demonstrate the problem quite well. The resulting 3 angles would not be 45 degrees and it's easy to check visually (adding 2 of them would not be equal to 90 degrees)
Dec
8
comment Find value of sum of reciprocals of powers of a number
@Wood or x=1 (instead of 0.5)
Dec
4
comment Why is it that $f(x)$ is even if $f(-x) = f(x)$?
Definitions do not require proof. It's like baptizing. I baptized myself ypercube. Therefore ypercube is me. We baptized even functions all those functions f that satisfy f(x) = f(-x) for all x that f is defined.
Nov
20
comment How to find a general sum formula for the series: 5+55+555+5555+…?
Shouldn't the summation be for k=0 up to n-1?
Nov
12
comment Open mathematical questions for which we really, really have no idea what the answer is
@pew Added the link above. But he thinks that if we find a proof, it will probably be an existentiaal one, not an actual algorithm, useful in practical applications.
Nov
12
comment Open mathematical questions for which we really, really have no idea what the answer is
For the record, Knuth said that he thinks P=NP is more plausible, in a recent interview: informit.com/articles/article.aspx?p=2213858
Nov
7
comment Evaluate $\int_{-1}^{1} \exp(x+e^{x})\,dx$
You are fast ;)
Nov
7
comment Subgroups of Order $p^2$ in $\mathbb{Z}_p \oplus \mathbb{Z}_p$
You already say that the order of the group is $p^2$. So you have a bag with $X=p^2$ items. You take $X$ items and put them in another bag. How many ways to do this?
Nov
7
comment Examples of mathematical discoveries which were kept as a secret
I'm not anything near an expert in math history but you are saying that we have no evidence of Fermat proving for example that $x^4+y^4=z^4$ has no solutions or any of the many theorems that carry his name?
Nov
7
comment Examples of mathematical discoveries which were kept as a secret
Very interesting! Hidden by accident.
Nov
7
comment cardinality of set of finite groups
@user1729 I suggested an edit, perhaps this can be salvaged.
Nov
7
comment cardinality of set of finite groups
Where in your question do you mention isomorphism and isomorphism classes?
Nov
7
comment cardinality of set of finite groups
For the same reason there is no set of all sets. It would lead to contradiction.
Nov
7
comment cardinality of set of finite groups
Is there a set of all finite groups? You first have to prove (or disprove) that.
Nov
6
comment Reference request for unknown mathematical constant
Using $\frac{1}{m(m+1)^2} = \frac{1}{m} - \frac{1}{m+1} - \frac{1}{(m+1)^2}$
Nov
6
comment Does the A001921 linear recurrent integer sequence always yield composite numbers?
Why you considered $a(64n+17)$ and not $a(64n+33)$?
Nov
6
comment Union of power sets of the counting numbers
It's an infinite set that its elements are finite.
Nov
6
comment Prove that $\frac{1}{a^3(b+c)}+\frac{1}{b^3(a+c)}+\frac{1}{c^3(a+b)}\ge \frac32$
How will you use the Cauchy-Schwarz? Do you mean the AM-GM inequality perhaps?