5,495 reputation
928
bio website math.uwaterloo.ca/~j2rosen
location Waterloo, Ontario
age 30
visits member for 2 years, 8 months
seen 21 hours ago

I am a postdoc in math at the University of Waterloo


Dec
8
awarded  Caucus
Nov
22
comment Most ambiguous and inconsistent phrases and notations in maths
There can be ambiguity when there's more than one degenerate object of a certain kind. E.g. if $V$ is a vector space, certainly $\{0\}\subset V$ is a trivial subspace. Is $V$ also a trivial subspace?
Nov
18
answered If the number $x$ is algebraic, then $x^2$ is also algebraic
Nov
11
awarded  Tumbleweed
Nov
10
comment When does a ring map $R\to S$ produce a group epimorphism $GL_n(R)\to GL_n(S)$?
To clarify: do you want $\overline{f}$ to be a surjection for every $n$, or just for some fixed $n$?
Nov
10
answered In what topological abelian groups does convergence to zero imply summability?
Nov
10
comment if (I-AB) invertible is (I-BA) invertible?
In this example $I-AB=\left[\begin{array}{cc}1&-1\\0&1\end{array}\right]$ is invertible
Nov
10
comment if (I-AB) invertible is (I-BA) invertible?
$A=\left[\begin{array}{cc}0&1\\0&0\end{array}\right]$, $B=\left[\begin{array}{cc}0&0\\0&1\end{array}\right]$ is a counterexample
Nov
4
asked Map from Galois extension to its third tensor power
Nov
1
comment Algebraic results using lower K-theory as a blackbox
Yes, a basis for $S$ as an $R$-module is $1,i$.
Nov
1
comment Algebraic results using lower K-theory as a blackbox
For problem B, $\mathbb{R}[x,y]/(x^2+y^2-1)\subset\mathbb{C}[x,y]/(x^2+y^2-1)$ is a counterexample. I asked JB about this problem, and he said he wasn't sure what the right statement was supposed to be.
Oct
27
reviewed Approve Does equality of antiderivatives imply equality almost everywhere?
Oct
27
reviewed Reject Randomize algorithm three times for modified values
Oct
10
revised 100 sequential parking spaces
added 2 characters in body
Oct
10
revised 100 sequential parking spaces
added 3 characters in body
Oct
10
answered 100 sequential parking spaces
Oct
2
reviewed Approve Compactness of the identity operator
Sep
20
comment Closed form for ${\large\int}_0^1\frac{\ln(1-x)\,\ln(1+x)\,\ln(1+2x)}{1+2x}dx$
Very interesting! I am surprised to see this integral expressed in terms of the "single" polylogarithm.
Sep
17
awarded  Nice Answer
Sep
17
revised Closed form for ${\large\int}_0^1\frac{\ln(1-x)\,\ln(1+x)\,\ln(1+2x)}{1+2x}dx$
added 6 characters in body