Thomas Belulovich
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 Mar2 revised If $\tan x=\sin x/\cos x$ then what is $\tan 3x$ equal to? fixed typo Dec10 awarded Enlightened Dec10 awarded Nice Answer Dec9 awarded Caucus Nov30 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 Nov30 answered For $n\times n$ matrices $A,B,$ and $C,$ is it always true that $\mathrm{rank}(ABC)\leq\mathrm{rank}(AC)$? Nov21 comment Indiscrete space has trivial fundamental group What have you tried? Have you considered which functions into an indiscrete space are continuous? Nov12 answered The jelly bean box problem Sep24 awarded Autobiographer Aug5 awarded Yearling Jul3 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. Jun26 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 $i+j$. Jun26 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. Jun26 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.) Jun10 answered Shortest path between wikipedia articles May23 awarded Nice Answer May21 answered induced sequence exact May16 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 $W$. May16 answered Why is this called the orthogonal projection of $u$ on $W$ if $proj_Wu$ is not orthogonal to $u$? May16 answered Nuking the Mosquito — ridiculously complicated ways to achieve very simple results