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Nov
14
answered What does it mean when a number 'y' is pseudoprime to base 'x'
Nov
14
comment What does it mean when a number 'y' is pseudoprime to base 'x'
Based on your edit: What is your actual question now? The wiki page seems to answer your question completely. So please edit the question and clarify what exactly is unclear to you on the wiki page.
Nov
14
comment What does it mean when a number 'y' is pseudoprime to base 'x'
Google first hit for "pseudoprime": en.wikipedia.org/wiki/Pseudoprime . Note that most commonly Fermat's pseudoprimes are meant.
Nov
14
comment Prove that the only $3×3$ matrices which commute with any $3×3$ matrices are of the form $cI$ for some scalar $c$…
+1. Just note that to me it seems that $\mathcal{M}_n(\mathbb{R})$ is quite a French notation, the internationally recognized notation is $\mathbb{R}^{n\times n}$.
Nov
14
revised Is there in literature a descriptive abbreviation phrase for “for infinitely many $n$”?
added 8 characters in body
Nov
14
answered Is there in literature a descriptive abbreviation phrase for “for infinitely many $n$”?
Nov
3
comment Eigenvalues of reflection
Would upvote twice if I could. The simplest argument ever for this kind of problem.
Oct
23
revised Proof for divergence of $\int_1^\infty \cos(x^\frac{3}{4})$
edited body
Oct
23
comment Proof for divergence of $\int_1^\infty \cos(x^\frac{3}{4})$
@nayrb I believe that your comment should really be expanded into another answer. It's a very interesting method of showing integral divergence.
Oct
23
answered Proof for divergence of $\int_1^\infty \cos(x^\frac{3}{4})$
Oct
16
comment Is Aleph 0 a natural number?
@Deduplicator Exactly what Noah says. Cleverly taking down aleph-null bottles can be done forever :-)
Oct
16
comment Is Aleph 0 a natural number?
@mvw You're so slow! :D "Aleph-null bottles of beer on the wall, Aleph-null bottles of beer, Take aleph-null down, and pass it around, Aleph-null bottles of beer on the wall."
Oct
3
comment Showing $\pi/(2\sqrt3)=1-1/5+1/7-1/11+1/13-1/17+1/19-\cdots$
@Winther What a surprise! :D /yo' out
Oct
3
comment Showing $\pi/(2\sqrt3)=1-1/5+1/7-1/11+1/13-1/17+1/19-\cdots$
@Winther It wouldn't be unusual for 2 and 3 to be excluded from somewhere. I actually made the comment because at first I thought: What? A precise formula involving a sum over primes?!
Oct
3
comment Showing $\pi/(2\sqrt3)=1-1/5+1/7-1/11+1/13-1/17+1/19-\cdots$
I wonder, is it primes you sum over, or $6k\pm1$? :-)
Oct
3
comment If $G=\mathbb{Z}_a \times \mathbb{Z}_b$, find a particular subgroup of $G$.
Have you tried writing it up for $a=6$ and $b=10$? What have you gotten as $M$ and what would $H$ be then? Can you generalize it to other cases?
Oct
3
comment regular expressions $(a+b)^*$
@user270494 The language $\{a,b\}$ contains just the two words of length $1$. You probably meant the language $\{a,b\}^*$.
Oct
3
answered Definition of $\sigma$-finite
Oct
3
answered Why proof by induction is working.
Oct
2
comment Determinant of a specially structured matrix
Can't you put $\mathbf u:=\mathbf e$ and $\mathbf v:=b\mathbf e$ (or vice versa) to avoid the radicals?