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visits member for 5 years, 9 months
seen Jun 13 at 22:18

Jun
13
answered Reference for an unbiased definition of a symmetric monoidal category
Jun
12
comment A good place where to learn about derived functors
Fixed. I've moved jobs since writing this answer, and the link was to my old website.
Jun
12
revised A good place where to learn about derived functors
updated link
Jun
6
comment For a ring $k$ and a set $X$, what are the $k$-algebra homomorphisms $k^X \to k$?
Thanks, Eric. So in particular, whether there exist nontrivial maps $k^X \to k$ depends only on $X$ and the cardinality of $k$, at least when $k$ is a field.
Jun
6
accepted For a ring $k$ and a set $X$, what are the $k$-algebra homomorphisms $k^X \to k$?
Jun
4
comment For a ring $k$ and a set $X$, what are the $k$-algebra homomorphisms $k^X \to k$?
@ArturoMagidin: Thanks for the edit, Latexifying the title. I seem to recall a meta discussion a while ago in which various people said Latex in titles should be kept to a minimum. It was a matter of speeding up rendering on slow devices or slow network connections. That's why I wrote the title in plain text. But I'm not so bothered about it that I'm going to change it back.
Jun
4
revised For a ring $k$ and a set $X$, what are the $k$-algebra homomorphisms $k^X \to k$?
improved wording
Jun
4
comment For a ring $k$ and a set $X$, what are the $k$-algebra homomorphisms $k^X \to k$?
@TomGoodwillie: Thanks! Your argument implies that if $|X| \leq |k|$ then there are no nontrivial homomorphisms $k^X \to k$, doesn't it?
Jun
4
comment For a ring $k$ and a set $X$, what are the $k$-algebra homomorphisms $k^X \to k$?
@YCor: I don't have a particular interest in large cardinals, thanks, but neither do I particularly want to rule out sets of large cardinality.
Jun
4
asked For a ring $k$ and a set $X$, what are the $k$-algebra homomorphisms $k^X \to k$?
May
26
awarded  Good Question
Mar
3
awarded  Famous Question
Mar
2
comment On the coherence theorem for bicategories
If you want a quick overview of the situation, you could try the slides here, especially pages 8 and 14: maths.ed.ac.uk/~tl/toronto
Jan
22
awarded  Popular Question
Jan
18
awarded  Good Answer
Jan
17
awarded  Enlightened
Jan
16
awarded  Nice Answer
Dec
2
awarded  Notable Question
Dec
1
comment History of integral notation for coends
Do you know how we came to write the end variable at the bottom of the integral sign and the coend variable at the top?
Dec
1
comment What theorem constructs an initial object for this category? (Formerly “Integrability by abstract nonsense”)
@IanMorris Thanks for pointing out the dead link. I still haven't got round to publishing it, but meanwhile I've proved some further results: maths.ed.ac.uk/~tl/cambridge_ct14 and golem.ph.utexas.edu/category/2014/07/…