6,835 reputation
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bio website math.upenn.edu/~frankelb
location Philadelphia, PA
age
visits member for 2 years, 10 months
seen 10 hours ago

I'm currently (fall 2013) a third year graduate student at the University of Pennsylvania. My thesis, still in its infancy, concerns maps from fundamental groups of complete curves over fields of positive characteristic into linear groups.


Apr
14
comment suming an infinite series
Your sums are set up correctly. Hint: These are geometric series.
Apr
14
reviewed Edit suggested edit on Cardinality, Finite Sets Proof
Apr
14
revised Cardinality, Finite Sets Proof
adjusted tags
Apr
14
revised $R[[x]]$ for a Noetherian ring $R$?
edited body
Apr
14
comment $R[[x]]$ for a Noetherian ring $R$?
@massy255 Thanks. Just fixed it!
Jan
5
awarded  Yearling
Dec
19
awarded  Nice Answer
Dec
9
revised A couple questions on radical extensions
added 137 characters in body
Dec
9
comment A couple questions on radical extensions
@user39947 Thanks for pointing out the mistake. I'll amend the post now.
Dec
5
reviewed Approve suggested edit on Example of a continuous function which is not uniformly continuous at a given interval.
Dec
5
comment Question about a proof in Washington's book “Introduction to Cyclotomic Fields” of the ramification in $\mathbb {Z}_p$-extension
@Amine I don't have a reference (probably somewhere in Serre), but I've already sketched the proof for you. Once you parse what I've written using the definition of projective limits, decomposition, and inertia groups, it should be pretty immediate.
Dec
5
comment Question about a proof in Washington's book “Introduction to Cyclotomic Fields” of the ramification in $\mathbb {Z}_p$-extension
@Amine I'm not familiar with Lorenz's book so I could be misinterpreting his notation, but $U^{(1)}$ generally (for example, in Serre) means the group of units whose residue class is $1$. Washington calls this group $U_1$. So $U\cong k^* \times U^{(1)}$.
Dec
5
comment Question about a proof in Washington's book “Introduction to Cyclotomic Fields” of the ramification in $\mathbb {Z}_p$-extension
@Amine It's certainly true for all finite extensions. Now take projective limits to get the statement for infinite extensions, using the fact that if $L/K/F$ is an abelian tower of fields, the decomposition group of $L/F$ surjects onto $K/F$ under the restriction homomorphism.
Dec
5
comment Prove $\sup A \le \inf B$.
Yes, that would be a very good place to start.
Dec
5
revised Prove $\sup A \le \inf B$.
added 12 characters in body
Dec
5
revised The set of all things. A thing itself?
edited tags
Dec
5
answered Question about a proof in Washington's book “Introduction to Cyclotomic Fields” of the ramification in $\mathbb {Z}_p$-extension
Dec
4
reviewed No Action Needed Combinatorial word problems (Discrete math)
Dec
4
reviewed No Action Needed Number of different partitions of N
Dec
4
reviewed Approve suggested edit on Chain homotopy inverse to inclusion