2,486 reputation
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location Providence, RI
age 27
visits member for 4 years, 4 months
seen Dec 19 at 5:03

Graduate student in topology.


Dec
10
awarded  Enlightened
Dec
10
awarded  Nice Answer
Dec
9
awarded  Caucus
Nov
30
revised For $n\times n$ matrices $A,B,$ and $C,$ is it always true that $\mathrm{rank}(ABC)\leq\mathrm{rank}(AC)$?
added 80 characters in body
Nov
30
answered For $n\times n$ matrices $A,B,$ and $C,$ is it always true that $\mathrm{rank}(ABC)\leq\mathrm{rank}(AC)$?
Nov
21
comment Indiscrete space has trivial fundamental group
What have you tried? Have you considered which functions into an indiscrete space are continuous?
Nov
12
answered The jelly bean box problem
Sep
24
awarded  Autobiographer
Aug
5
awarded  Yearling
Jul
3
comment Prove that this affine transformation is a translation
I expect $\phi(P)P$ is the affine hull (line through) the distinct points $\phi(P)$ and $P$. This is why $\phi$ has to have no fixed points.
Jun
26
comment Proving any N x M undirected two dimensional grid is bipartite
This works. It's more concise to say that you are coloring based on the parity of $i+j$.
Jun
26
comment Proving any N x M undirected two dimensional grid is bipartite
You didn't color all the vertices -- only ones where one coordinate is even and the other odd. However, the idea is sound -- coloring based on parity will work here.
Jun
26
comment Question from Munkres algebraic topology section 58: retractions
It would probably good for your question to say what $j_*$ is (I assume the map induced on $\pi_1$, but it would be good to specify.)
Jun
10
answered Shortest path between wikipedia articles
May
23
awarded  Nice Answer
May
21
answered induced sequence exact
May
16
comment Why is this called the orthogonal projection of $u$ on $W$ if $proj_Wu$ is not orthogonal to $u$?
$w_1$ is called an orthogonal projection of $u$ because $w_1$ differs from $u$ by a vector $w_2 = u-w_1$ that is orthogonal to $W$.
May
16
answered Why is this called the orthogonal projection of $u$ on $W$ if $proj_Wu$ is not orthogonal to $u$?
May
16
answered Nuking the Mosquito — ridiculously complicated ways to achieve very simple results
Mar
25
comment Homotopy equivalences
Hint: denote $G = G_f$ to emphasize the dependence of $G$ on $f$. Suppose $f_1,f_2 : X \to Y$ are homotopic. Can you show $G_{f_1} = G_{f_2}$?