meta user
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| bio | website | combinatorialgames.wordpress.… |
|---|---|---|
| location | Somewhere | |
| age | 25 | |
| visits | member for | 1 year, 2 months |
| seen | yesterday | |
| stats | profile views | 61 |
I have years of experience helping people with math(s) on academic forums, over the internet, and in person, both with groups and one-on-one.
I also have an amateur interest in combinatorial game theory and occasionally update a blog with some basic exposition on the subject (see website).
If you need to contact me, use the e-mail address at this link.
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Jan 11 |
accepted | Continuous partials at a point but not differentiable there? |
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Jan 11 |
comment |
Help make Wonder Woman's box big. @MaoYiyi, consider rewriting your proposed solution as an answer and accepting it. I came across this when viewing problems with no answers. |
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Jan 11 |
comment |
Non-ZFC set theory and the hyperreals: problem solved? Also, as pointed out on math overflow, the usual construction is unique up to isomorphism if you include CH. I'd answer the question except I don't know for certain that $\mathbb{Z}^*$ would sit inside $\mathbf{Oz}$. |
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Jan 11 |
revised |
Volume of a sphere by “adding” half-spheres of lower dimension Added multivariable-calculus tag for appropriate exposure |
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Jan 11 |
suggested | suggested edit on Volume of a sphere by “adding” half-spheres of lower dimension |
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Jan 11 |
answered | Should the domain of a function be inferred? |
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Jan 11 |
revised |
Should the domain of a function be inferred? Added tags |
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Jan 11 |
suggested | suggested edit on Should the domain of a function be inferred? |
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Jan 11 |
comment |
Is the definition of degenerate bilinear forms equal to the two variables? en.wikipedia.org/wiki/Bilinear_form#Maps_to_the_dual_space says you should have both conditions. |
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Jan 11 |
comment |
Nimnumber of three pile Wythoff Game Are you asking about the Grundy values (sizes of equivalent Nim heaps) of Wythoff Game positions? Or a strategy for Wythoff's game? etc. |
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Dec 29 |
revised |
Math game, the least number of operations to get N from 0 removed CGT tag |
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Dec 29 |
suggested | suggested edit on Math game, the least number of operations to get N from 0 |
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Dec 8 |
awarded | Enthusiast |
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Nov 19 |
comment |
Point of inflection, local max, local min What do your notes/textbook say about local maxima and points of inflection? |
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Nov 19 |
comment |
Prove subspace of finite dimensional vector space is finite dimensional You don't have to use the plus-minus theorem, but if you really want to, try to think of a set of vectors to apply the "plus" or the "minus" to yield a contradiction with W being finite dimensional. |
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Nov 18 |
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Prove subspace of finite dimensional vector space is finite dimensional Suppose for sake of contradiction that W isn't finite dimensional. That will probably contradict V being finite dimensional. |
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Nov 18 |
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Can we ascertain that there exists an epimorphism $G\rightarrow H$? @HagenvonEitzen I think Olivier Bégassat might have been joking since the pairwise intersections of the lifetimes of Archimedes, Gauss, and Gromov are all empty. |
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Nov 18 |
comment |
Cosets and Index If $G=\langle\sigma\rangle$, which has five elements, then the cosets you can get from any element of $G$ would be the same as $G$: $(1,3,4,2,5)G=G$, etc. And the coset you'd get from $(2,3)$ would be the same as the coset you'd get from $(153)(24)$ since $\left((153)(24)\right)(1,3,4,2,5)=(2,3)$. As you go through the elements of $S_5$, you generate each 5-element coset 5 separate times; there are 24 of them. Cosets never overlap: math.stackexchange.com/questions/99421 and have the same size (finite grps): Thm 4.9 in math.uconn.edu/~kconrad/blurbs/grouptheory/coset.pdf |
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Nov 18 |
comment |
Cosets and Index Actually, I could stand to be a little clearer. Since in every group (including $S_5$), elements have inverses, if you take any single element $g$ in the group, and you want to get an arbitrary element $h$, by multiplication, it's like you want to find the $k$ such that $gk=h$. But the answer to that is just $k=g^{-1}h$. So yes, you can get every element of $S_5$ just by multiplying things by $\sigma$. However, the point here is that you're not interested in getting all the elements of $S_5$ element by element, you want cosets to generate $S_5$... |
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Nov 18 |
comment |
Cosets and Index @Brian re:single element cycles: It's a habit I picked up so I/my readers don't forget whether "(123)" is an element of S_5 or S_6, etc. It also avoids the confusion that might arise because I don't know whether sizz uses $\mathbf{1}$ or $e$ or $\mathrm{id}$ for identity elements. But you're right to point out it's non-standard and wasteful when there's no chance for confusion. sizz, you also need to multiply by the identity, which is also part of the subgroup generated by anything, and which coincidentally is $\sigma^5$. Also, just be careful: $(6,3,2)$ isn't part of $S_5$ |
