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21848
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location Waterloo, Canada
age 22
visits member for 3 years
seen 13 hours ago

Mathematical Physics Major at the University of Waterloo.


22h
awarded  Popular Question
Apr
10
comment 2D is to face as 3D is to?
Generally, we stop inventing words and use the creative name of $k$-face or $k$-cell for a $k$-dimensional analogue of a face.
Apr
9
answered Vertex/Edge Independence Proof
Apr
7
awarded  Yearling
Apr
7
comment Tell me problems that can trick you
What is $S_n(\mathbb{R})$?
Mar
30
answered subspaces, nullspace, column space, row space
Mar
30
revised Degree sequence of connected graphs
edited body
Mar
30
revised Degree sequence of connected graphs
added 127 characters in body
Mar
30
answered Degree sequence of connected graphs
Mar
27
answered $n$ regular graph with $2n$ vertices that doesn't contain triangle must be $K_{n\ n}$
Mar
27
comment $n$ regular graph with $2n$ vertices that doesn't contain triangle must be $K_{n\ n}$
@Ashot you need to mention the triangle-free property. That's critical. This question arises in the context of Mantel's theorem.
Mar
24
answered how to find three vertices of a triangle.
Mar
23
answered Hamiltonian $C_n$ Proof
Mar
17
comment Nullspace and column space
I'm not sure what you mean by "perpendicularity" although I suspect that it's another term for the orthogonal complement (am I right?). If that's the case, then this is simply a consequence of the fact that the rowspace is the orthogonal complement of the nullspace. For symmetric matrices, the rowspace and the columnspace are equal, so this applies to columnspaces of symmetric matrices too.
Mar
16
answered A question on eigenvalues
Mar
12
answered Math problem puzzle
Mar
12
answered Question about eigenvalues and eigenvectors
Mar
12
comment How can I explain to my professor his argument invokes the AC?
The difference between the union and the professor's argument is that the union grabs everything so that there is no choice involved. The professor has taken a specific subset of open balls, precisely one ball per point $x$. I agree that seems to involve some form of choice.
Mar
11
revised Elementary proof for $\text{rank} \left(A \otimes B \right) = \text{rank}A\cdot \text{rank}B$
added 17 characters in body
Mar
11
answered Elementary proof for $\text{rank} \left(A \otimes B \right) = \text{rank}A\cdot \text{rank}B$