125,795 reputation
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bio website math.ubc.ca/~israel
location Richmond, Canada
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visits member for 3 years, 5 months
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I'm an Emeritus Associate Professor of Mathematics at University of British Columbia and an Optimization Algorithms Researcher at D-Wave Systems in Burnaby BC


Aug
14
answered Growth Rate of Alternating Sign Matrices
Aug
14
comment What exactly are the curves that are a best fit to the Harmonic Cantilever?
$Z_n = H_n = \ln(n) + \gamma + O(1/n)$. $c = \exp(-\gamma)$ gives you $n = c \exp(Z_n) (1 + O(1/n))$.
Aug
14
answered Necessary that $A \cap M = \emptyset $ in $A\cup M \sim M$?
Aug
14
answered $f: \mathbb{R}^2 \to \mathbb{R}$ is a continuously differentiable function (of class $C^1$). Show that mapping f can not be one-to-one mapping.
Aug
14
comment What exactly are the curves that are a best fit to the Harmonic Cantilever?
Look up en.wikipedia.org/wiki/Euler%E2%80%93Mascheroni_constant
Aug
14
answered Square root of a matrix that is the sum of other matrices, in terms of square roots of the component matrices
Aug
14
comment Relation between eigenvectors after transforming a nonsymmetric matrix to symmetric?
As long as $B$ is positive definite (and therefore nonsingular) you should get all of them. If $v$ is an eigenvector of $AB$, then $v = B^{-1/2} u$ where $u = B^{1/2} v$ is an eigenvector of $B^{1/2} A B^{1/2}$.
Aug
14
comment When a r.v. admits mean and variance?
OK, I'm letting you.
Aug
14
answered Space of matrices that commute with a given matrix
Aug
14
answered Paley-Wiener theorem for a sector $\{\zeta:-\epsilon<\arg(\zeta)<\pi+\epsilon\}$
Aug
13
answered In a non-Hausdorff space, can a compact subset fail to be closed?
Aug
13
answered Relation between eigenvectors after transforming a nonsymmetric matrix to symmetric?
Aug
13
answered When a r.v. admits mean and variance?
Aug
13
comment Function which is equal to a holomorphic function at 3 points
$$\dfrac{f(z) - f(p)}{z-p} - f'(p) = \dfrac{1}{2\pi i} \oint_\Gamma f(\zeta) \left( \dfrac{1}{(\zeta - z)(z-p)} - \dfrac{1}{(\zeta -p)(z-p)} - \dfrac{1}{(\zeta-p)^2} \right)\; d\zeta$$ $$ = \dfrac{z-p}{2\pi i} \oint_\Gamma \dfrac{f(\zeta)\; d\zeta}{(\zeta-p)^2 (\zeta-z)} $$
Aug
13
answered Function which is equal to a holomorphic function at 3 points
Aug
13
comment How do you formulate a vague notion into a mathematical expression?
You might look at something like Cliff Taubes "Modeling Differential Equations in Biology".
Aug
13
comment Help to understand and verify this question regards Spectral Thereom
Check that $T v = \lambda v$.
Aug
13
comment Prove that a function $f(n)$ counting the number of odd divisors multiplicative
... prime factorization...
Aug
13
comment What is the oldest open problem in geometry?
What does this have to do with the question? Maybe it could have been understood, but if there's no record of it having been asked more than a few years ago it doesn't qualify.
Aug
12
comment How to find a nonlinear function $f:\mathbb{R}^2\to\mathbb{R}^2$ that is almost linear in the sense $f(\alpha (a,b))=\alpha f(a,b)$?
Another is $a \;\text{signum}(b)$.