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seen Aug 24 at 1:40

Aug
8
comment Average deviation of group sizes
meta discussion: meta.mathoverflow.net/questions/1837/…
Aug
1
comment Projection of a hypersurface from a point
Note that this question was also asked at MO: mathoverflow.net/questions/177526/… (It is considered good form to link to the other question in cases of cross-posting, so that efforts to answer are not duplicated.)
Jul
19
comment Associated prime ideals and local cohomology
Question 1 looks like a homework exercise, or at least an exercise from a graduate text. Such exercises are occasionally entertained here, if the poster explains where he/she is having a difficulty, but usually such questions are better asked at mathematics.stackexchange. Question 2 doesn't look like a question at all. What was the question?
Jul
6
comment Compact-Open topology on C(X).
Assuming the second family forms a base at all (it's not clear to me it does), it contains all sets of the form $[A, V]$ (this is the subfamily consisting of 1-fold intersections). Then, since the first topology is the smallest topology containing sets of this form, it must be contained in the second topology. Am I missing something?
Jul
5
comment holomorphic map between compact Riemann surfaces
@BrunoJoyal But an open annulus is a union of open discs. (Perhaps the English threw you off?)
Jul
5
answered holomorphic map between compact Riemann surfaces
Jul
1
comment Points in a general Cantor set
Not only is it expected to have the same topological structure -- it does have the same topological structure. See en.wikipedia.org/wiki/Cantor_space#Characterization.
Jun
23
comment Hochschild cohomology of a formal quantization of an associative algebra
I personally feel that it would have been fine to post this at MO in the first place -- the level seems sufficiently high. Also, a lot of people do post at both sites; the main problem people have with such "cross-posting" is that it could lead to duplication of effort. Thus, as a minimum courtesy, one should at least link from each post to the other post if one decides to cross-post.
Jun
21
comment examples of polyclic groups
Migrating, as requested by the OP.
Jun
1
comment What are the uses of “squeezing”?
Possibly the OP will reject this as being another example of one of his bullet points, but I thought it was cute enough to record anyway. It does occur to me that squeezing arguments are commonplace in advanced calculus courses, to prove e.g. that continuous functions are Riemann integrable.
Jun
1
answered What are the uses of “squeezing”?
May
30
comment A paratopological group with intersection of neighborhoods of a point non-closed
@user138171 Isn't the Sorgenfrey line a counterexample? (This is the additive group $\mathbb{R}$, with topology given by a base consisting of half-open intervals $[a, b)$ with $a < b$.)
May
29
revised A paratopological group with intersection of neighborhoods of a point non-closed
added 563 characters in body
May
29
answered A paratopological group with intersection of neighborhoods of a point non-closed
May
29
comment Are Exponential and Trigonometric Functions the Only Non-Trivial Solutions to $F'(x)=F(x+a)$?
Possibly the question becomes more interesting (or tractable) if $F$ is assumed analytic? If $F$ is merely $C^\infty$, then taking for example $a = 1$ and any $C^\infty$ function $F$ such that $F^{(n)}(0) = 0 = F^{(n)}(1)$ for all $n \geq 0$, the extension of $F$ to any interval $[n-1, n]$, for $n \in \mathbb{Z}$, can be defined recursively by appealing to the functional equation.
May
11
comment Integral of Bernstein Polynomials
Although something looks wrong here, the way it's written. The function $B_n$ as defined depends on values of $f$ over the interval $[0, 1]$, not over $[a, b]$. I presume there's a typo somewhere.
Apr
27
comment Are mathematical articles on Wikipedia reliable?
So the point is that Riskin's example is perhaps not a good one, since professional mathematicians do use those terms rather interchangeably -- it's not actually "wrong" as he claims.
Apr
27
comment Are mathematical articles on Wikipedia reliable?
Incidentally, it's "etc.", not e.t.c.
Apr
27
comment Are mathematical articles on Wikipedia reliable?
@SanathDevalapurkar No, that's just one meaning of "indeterminate" (usually occurring as part of the phrase "indeterminate form" used in elementary calculus). And "variable" as used by mathematicians typically doesn't mean "something unknown", but rather is a formal symbol, typically invoked in the description of a free algebraic structure and the like. See for example ncatlab.org/nlab/show/polynomial and ncatlab.org/nlab/show/variable
Apr
27
comment Are mathematical articles on Wikipedia reliable?
Mathematicians do use the terms "variable" and "indeterminate" pretty interchangeably, I find, as in "polynomial ring in $n$ variables" or "polynomial ring in $n$ indeterminates".