Mark S.

601 reputation

314

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.

	601 reputation	bio	website	combinatorialgames.wordpress.…	visits	member for	1 year, 2 months
314 badges		location	Somewhere		seen	yesterday

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Nov 18	comment	Cosets and Index In response to a deleted comment, $\left((1,2,4,5)(3,6)\right)^2$ sends $3$ to $6$ and then back to $3$, so it should have $(3)$. Similarly for $(6)$. However, it sends $1$ to $2$ and then to $4$, and $4$ to $5$ and then to $1$, so it should have $(1,4)$ as part of its disjoint cycle decomposition. Similarly, it sends $2$ to $4$ and then to $5$, and $5$ to $1$ and then to $2$, so it should have $(2,5)$.
Nov 18	comment	Cosets and Index (2,3) is not in G. (2,3) is in $S_5$ (and I just picked it randomly), and as such, it gives rise to a left coset of G. If I had picked something in G (say, (1,3,4,2,5)) then the left coset (1,3,4,2,5) G would just be G again. It wouldn't be a new coset.
Nov 18	revised	Cosets and Index Added a nontrivial coset
Nov 18	answered	Cosets and Index
Nov 17	awarded	Autobiographer
Nov 17	answered	How would you make a (physical) dodecahedron with edges instead of faces?
Nov 14	revised	writing a translation and rotation as product of two reflections added l-a tag
Nov 14	suggested	suggested edit on writing a translation and rotation as product of two reflections
Nov 14	comment	writing a translation and rotation as product of two reflections If this is a homework problem, it would help if you would tag it as such. Also, as it's a linear-algebra problem, that tag would be good too.
Nov 13	revised	Counting small subsets of a given set Added explicit calculation.
Nov 13	answered	Counting small subsets of a given set
Nov 13	comment	Transferability of space properties via continuous functions Klara, on Stack Exchange, you can also show your appreciation for answers by upvoting them (and eventually accepting them if they end up being a good enough answer for your needs).
Nov 13	comment	How to prove this expression? Just like (1+2+4+6)/2=(1/2)+1+2+3 (look at the parentheses), (jl + jmc + lkc + kmc^2) / c=(jl/c)+jm+lk+kmc. Think about what that means about (jl + jmc + lkc + kmc^2) % c.
Nov 13	comment	Transferability of space properties via continuous functions Klara, have you written down the definitions of separable(Lindelof) and continuous functions yet? That would be a good start. Also, it might help people find your question if you edit the title to mention either something about separable and/or the fact that it's not properties of "continuous functions" you want to transfer, but rather properties of "spaces" via a continuous function.
Nov 13	awarded	Revival
Nov 13	answered	Multinomial Distributions
Nov 13	comment	Prove that a function is a total function (as opposed to a partial function) Well, you're probably not expected to worry about formally proving it completely rigorously at this level. But you seemed worried about rigor, so I described what more rigor would be like. If you feel this question is answered you can either accept my answer or add an answer of your own and accept that (since you had an answer first), or I think you can vote to delete your question if you really want.
Nov 13	comment	Maximal and Minimal Elements To clarify, the order you're using for your collection is $\subseteq$. And you can know without drawing the diagram by just thinking "which sets contain no proper subsets from the collection", etc.
Nov 12	answered	Prove that a function is a total function (as opposed to a partial function)
Nov 12	comment	Partial Ordering and Covering Relations "there is no transitivity" is a little vague because it's not clear whether you're asking about the binary relation "covers" or the binary relation ≺. I tried to handle both cases in my answer.