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comment Right English wording for “counterexamples to a theorem”
While it may not be strictly correct, "Counterexamples to the Banach fixed-point theorem" is certainly catchy! Specially if you're giving a talk.
Aug
26
answered Works of Kurt Gödel
Aug
26
comment What is the integer part of $\sum_{i=2}^{9999} \frac {1}{\sqrt i}?$
Try a Riemann sum. More precisely, lower and upper sums in a Darboux integral.
Aug
26
comment How to determine a kind of distance between two permutations?
See stackoverflow.com/questions/7797540/….
Aug
26
comment How to determine a kind of distance between two permutations?
You're right, sorry for the noise.
Aug
26
revised How to determine a kind of distance between two permutations?
added 14 characters in body
Aug
26
comment Origin of the word Mathematics and in which condition it did come of?
Try also hsm.stackexchange.com.
Aug
26
answered How to determine a kind of distance between two permutations?
Aug
26
comment When SVD has repeated singular values?
The title does not reflect the question asked at the end.
Aug
26
comment When SVD has repeated singular values?
All singular values of the identity matrix are the same... For a more general case, consider a diagonal matrix that is not a multiple of the identity.
Aug
26
comment Notation Question $n$ $ < <$ $m$
Actually, << works in C too. Sorry for the noise.
Aug
26
comment How to remember proofs in group theory
The question is too broad. Perhaps you could ask a concrete question about a specific proof you're having problems understanding.
Aug
25
comment Recognizing genuine proof obstructions
A wonderful story!
Aug
25
answered Prove that $1.49<\sum_{k=1}^{99}\frac{1}{k^2}<1.99$
Aug
25
answered For a prime integer $p \in \{2, 3, 5, \cdots\}$, is $pR$ a maximal ideal in $R$?
Aug
25
comment For a prime integer $p \in \{2, 3, 5, \cdots\}$, is $pR$ a maximal ideal in $R$?
Zero is the only maximal ideal in fields.
Aug
25
comment For a prime integer $p \in \{2, 3, 5, \cdots\}$, is $pR$ a maximal ideal in $R$?
Clearly not if $R$ is a field for instance.
Aug
25
answered Linear Algebra: which of the definition of subspace of a vector space is more correct?
Aug
25
answered Is there any element of order $51$ in the group $U(103)$
Aug
25
comment Is there any element of order $51$ in the group $U(103)$
There are $32=\phi(51)$ solutions, but $11$ is not one of them.