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I'm a graduate student at UC Berkeley, studying mathematical logic. I'm especially interested in reverse mathematics and abstract model theory.

13h
comment Polinominal equations
Explain why it is a good idea to do your own homework. Use reasoning to expand your explanation to find the general benefits of doing your own homework.
Jan
27
awarded  Notable Question
Jan
27
comment A Classification problem in measure theory
What is the motivation for this problem? Also, what sort of thing would count as a classification?
Jan
25
comment calculating E(Xt^2,Xt-h^2) with Xt normal(0,sigma^2)
Please do not ask homework questions here.
Jan
25
comment Are hyperreal numbers isomorphic to formal power series?
Again, "$No$" is from the surreals, not the hyperreals.
Jan
24
revised Maximum - Minum area
edited tags
Jan
24
comment Are hyperreal numbers isomorphic to formal power series?
Anixx, based on your most recent comment I think you might be confusing the hyperreals with the surreals, which are two very different things. In particular, there's no "special" element of 'the' hyperreals which we deem "$\omega$."
Jan
24
comment paradox about the Axiom of Choice?
Google is your friend: google.com/…
Jan
23
comment Book on Convergence Concepts in Probability without Measure Theory
Also, entirely separately - and I should have mentioned this in my first comment - measure theory is incredibly cool. See it now so you can see more later!
Jan
23
comment nonstandard models and mathematical theorems
Sneaky! I like it.
Jan
23
comment Book on Convergence Concepts in Probability without Measure Theory
Personally, I feel there's few things as useful as learning some measure theory as early as possible, especially if you're seriously interested in probability; but that's just my opinion.
Jan
23
answered On whether a formula of KP is $\Pi_3$
Jan
22
comment Matching power series to infinity
I was thinking in a slightly different direction: off the top of my head, I think we have a reasonable ring of power series for any index set $I$ which is the underlying set of a monoid $(I, *)$ such that for each $x$ in $I$, there are only finitely many pairs $y_1, y_2$ with $y_1*y_2=x$. But maybe there's another obstacle?
Jan
22
comment Matching power series to infinity
Actually, note that this establishes an equivalence: the statement "if every coefficient of the powerseries is a multiple of $c$, then the series is a multiple of $c$" is equivalent (over ZF) to the axiom of countable choice. And, if we generalize the class of formal power series to index sets other than $\omega$ in the natural way, we get equivalences with other forms of choice, too.
Jan
22
answered Matching power series to infinity
Jan
21
revised Decidability of diophantine equation in a theory
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Jan
21
revised Decidability of diophantine equation in a theory
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Jan
21
revised Decidability of diophantine equation in a theory
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Jan
21
answered Decidability of diophantine equation in a theory
Jan
21
comment Total formulae in a theory equivalent to $\Delta_0$ formulae in the theory?
(Also, in this context, it's good to give the provability predicate "$Bew$" a subscript, i.e., $Bew_{PA}(x)$ instead of $Bew(x)$.)