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2d
revised Question about the definition of “Prefix free”
converse example
2d
revised Question about the definition of “Prefix free”
explain example better2
2d
answered Question about the definition of “Prefix free”
Apr
22
comment Zeilberger's potential proof of Fermat's last theorem.
Can someone clarify what is suppposed to go in the two $\dots$?
Apr
5
reviewed Approve General solution of $y''+y'=0$
Apr
3
reviewed Approve rank of a matrix?
Apr
3
reviewed Approve How can I retain the mathematics that I've supposedly learnt?
Apr
3
reviewed Approve How to represent a number in such a way that no more than 2 consecutive digits are the same?
Apr
3
reviewed Reject A linear basis compatible with a family of subspaces
Apr
3
reviewed Approve Formula for finding the Roots of a cubic polynomial and nature of roots depending on the discreminant
Apr
3
revised Infinitely many $n$ such that $n^2+1$ is squarefree
explain what form
Apr
3
comment How to factor $\frac{27}{125}a^6b^9-\frac{1}{64}c^{12}$
It looks like Wolfram's alternative form isn't the same thing because $\frac{576}{320} \ne \frac{27}{125}$. But it's not at all clear to me what you are trying to do. Do you want to simplify this expression somehow?
Apr
3
revised Questions about partial derivative notation in Evan's PDE book
fix typo
Apr
3
revised Infinitely many $n$ such that $n^2+1$ is squarefree
define the form
Apr
3
reviewed Approve Expectation of inverse of a symmetric matrix with gaussian elements
Apr
3
revised Infinitely many $n$ such that $n^2+1$ is squarefree
explain
Apr
3
comment Infinitely many $n$ such that $n^2+1$ is squarefree
Nothing really analytic here except maybe $\frac{\pi^2}{6}$, but there is apparently an elementary proof of the Basel problem if that counts en.wikipedia.org/wiki/Basel_problem#A_rigorous_elementary_proof. You can use quadratic reciprocity to exclude $4 \cdot k + 3$ primes from the sum to get a tighter bound (but the first improvement would be to exclude composites). I will try to clarify some of the things Qiaochu mentions.
Apr
3
reviewed Approve Distribution agreeing with function
Apr
3
revised Infinitely many $n$ such that $n^2+1$ is squarefree
maybe not much
Apr
3
accepted How to prove that $5$ unit hypercubes cannot be positioned to cover a unit hypersphere?