Omar Antolín-Camarena

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2,162 reputation
815
bio website math.harvard.edu/~oantolin
location Cambridge, Massachusetts, USA
age 33
visits member for 3 years, 11 months
seen yesterday

Jul
18
reviewed Reject suggested edit on A Question Of Percentages
Jul
14
reviewed Approve suggested edit on How do I solve $y' = \sin(x - y)$?
Jul
14
reviewed Reject suggested edit on Both $R$ and $R/I$ are regular local rings
Jul
14
reviewed Approve suggested edit on Inverse Laplace Transform of a complicated function
Jun
12
revised Symmetry of Grassmanians
corrected a typo
Jun
11
comment Symmetry of Grassmanians
@PeterFranek: you're right, of course, I've deleted that bogus answer and replaced with a proof I hope is correct.
Jun
11
revised Symmetry of Grassmanians
Wrote correct proof in place of totally wrong proof
Jun
11
comment Infinite Direct Sums Vs. Infinite Direct Products
You say you want an explanation for the fact that in "so many categories" an infinite coproduct is the subset of the product where finitely many coordinates are "non-null"; but I disagree with your impression that this happens very often. Basically it happens in categories that are similar to Abelian groups, but it fails for example in these categories I'm fond of: sets, topological spaces, graphs, categories, groups, commutative rings, rings, partial orders, etc. I don't think you'll find a "deep explanation" that is substantially different from a proof that it holds in Abelian groups.
Jun
11
answered Symmetry of Grassmanians
Jun
11
reviewed Approve suggested edit on Infinite sum of logarithms
Jun
10
comment A question about the category Grp
I went down to the library and took a look at the book. Aluffi is not saying that you can remove mention of identities and inverses from the definition of group; he is merely saying that you don't need to mention identities and inverses in the definition of group homomorphism. This is true because any function between groups that preserves multiplication will automatically preserve the identity and inverses.
Jun
10
reviewed Approve suggested edit on Prove is linearly independent
Jun
4
comment How many rows will we draw in Hasse diagram?
'Group' would be a reasonable word to choose in non-technical English, but in math there is a big difference between 'set' and 'group', so it's good to learn the distinction, @kfir.
Jun
3
revised How many rows will we draw in Hasse diagram?
removed incorrect group-related tags
Jun
3
answered How many rows will we draw in Hasse diagram?
Jun
2
reviewed Edit suggested edit on Real $2\times 2$ matrix $X$ such that $X^2 + 2X= -5I$
Jun
2
revised Real $2\times 2$ matrix $X$ such that $X^2 + 2X= -5I$
I have written in Latex math expressions
Jun
2
reviewed Edit suggested edit on Trig question, inequality
Jun
2
revised Trig question, inequality
Formatting changes using Latex
May
29
reviewed Edit suggested edit on If $2^{200} - 2^{192}\cdot31 + 2^n$ is a perfect square, find value(s) of $n$.