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visits member for 3 years, 10 months
seen Mar 28 at 23:11

Jul
1
comment Understanding this partial derivative problem
this definitely does help, thank you
Jun
30
asked Understanding this partial derivative problem
Jun
4
accepted Does this equality always hold?
Jun
4
comment Does this equality always hold?
thank you mixedmath
Jun
4
comment Does this equality always hold?
excellent, thank you
Jun
4
comment Does this equality always hold?
@Fabian: thank you
Jun
4
asked Does this equality always hold?
May
24
awarded  Vox Populi
May
15
revised What is the best way to show that no positive powers of this matrix will be the identity matrix?
rolled back to a previous revision
May
14
accepted Are bounded sequences always strictly less than some fixed number $M$?
May
14
comment Are bounded sequences always strictly less than some fixed number $M$?
ok that totally makes sense, thank you for this answer.
May
14
asked Are bounded sequences always strictly less than some fixed number $M$?
May
9
awarded  Fanatic
May
6
accepted Who was the mathematician who thought “god” was out to get him?
May
6
comment Who was the mathematician who thought “god” was out to get him?
oh ok... well thanks all for clearing that up :)
May
6
comment Who was the mathematician who thought “god” was out to get him?
@Arturo: but how was he an atheist if he was convinced that "God" would not let him die? I mean for him to write the letter, he must have thought that there was a god, right?
May
6
asked Who was the mathematician who thought “god” was out to get him?
Apr
27
accepted How is it shown that a Hermitian matrix will be positive definite?
Apr
26
comment How is it shown that a Hermitian matrix will be positive definite?
Thank you very much, this is the sort of thing I was looking for. So a matrix is positive definite if it is hermitian, finite dimensional(is that what all that $k\leq n$ stuff means?), and the determinant is positive? Other question was about the hint, I tried it and got: $z = \left( \begin{array}{c} |i|^2 \\ -(1)(-i) \end{array}\right) \Rightarrow \overline{z}^{t}A_{1}z = 4$, did I misunderstand the inputs?
Apr
26
comment How is it shown that a Hermitian matrix will be positive definite?
@J.M.: sorry, but I still can't understand your idea... First, I thought I had already worked out the $m=1$ case, right? Second, I don't see where, how, or why to make $a,b,c,d$ evaluate to something manifestly nonpositive... Also when you say quadratic form, you are referring to a specific type of mapping, or just any polynomial with terms of degree 2?