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comment geodesic computation: “energy” minimization versus arc length minimization
Migrating to Math.SE on recommendation from several users...
Jan
30
revised Under what conditions the quotient space of a manifold is a manifold?
added another note
Jan
30
revised Under what conditions the quotient space of a manifold is a manifold?
added a reference
Jan
21
comment $\int_{-\infty}^{+\infty} e^{-x^2} dx$ with complex analysis
I'm guessing the downvote was in view of the obvious question: how do we know that fact about the normal distribution? Well, often it's proved starting from the fact that the OP is asking about, in effect running the very elementary calculus manipulations in your answer in reverse order. Meanwhile, there are various ways we know this fact, as mentioned by the OP, but he's asking specifically for a reason based on contour integration. So it seems you are not answering the question that was asked.
Jan
4
comment What is a number?
@vonbrand Yes, it's the one mentioned by Daniel Fischer. My own edition is in English.
Jan
2
comment dropping injectivity from multivariable change of variables
Also cross-posted at MO: mathoverflow.net/questions/227406/…
Dec
30
comment Limit problem with cosh and sinh
It's a fun problem, but off-topic for this site, which is for professional mathematicians and their graduate students to ask questions related to their research.
Dec
14
comment A structural view to the power set axiom: Is this axiom really justifiable?
Yes, so: my point is that you are addressing a question different from the one asked. OP wasn't asking about structures on the power set, but rather on the set of substructures.
Dec
14
comment A structural view to the power set axiom: Is this axiom really justifiable?
But $P(A)$, which I understand to be the power set of $A$, is not the set of substructures.
Nov
28
revised Help me prove equivalently of regular semigroup and group.
completely rewritten to give a proof
Nov
26
answered Help me prove equivalently of regular semigroup and group.
Nov
8
comment Logarithmic expansion with cosines
I do think this should have been migrated to Math.SE.
Oct
15
revised An elementary strict product inequality
corrected typo, reformatted for clarity
Oct
15
answered An elementary strict product inequality
Oct
15
comment An elementary strict product inequality
Alternatively, verify it for $\alpha = 1/2$. Then I expect (without thinking about it too hard, maybe I miss something) you should be able to get it for dyadic rationals in $(0, 1)$, and then you could appeal to continuity to get it for all reals $\alpha$ in $(0, 1)$.
Oct
15
comment An elementary strict product inequality
Of course, calculus is elementary. Out of curiosity, why do you want to avoid it? (You need at least some mild form of analysis even to define raising to a real power.)
Oct
15
comment An elementary strict product inequality
If convexity of $x \mapsto \log(1 + \exp(x))$ isn't enough of a hint, then you should ask at M.SE.
Oct
15
comment Where does the symbol $\mathcal O$ for sheaves come from?
I just learned from Keith Conrad at HSM that your speculation about order is correct: hsm.stackexchange.com/questions/2922/…
Oct
7
answered Does every odd prime divide a Mersenne number?
Sep
30
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