148,895 reputation
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bio website math.ubc.ca/~israel
location Richmond, Canada
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visits member for 3 years, 10 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


1d
answered Gateaux but not Frechet differentiable functional
1d
answered Moment generating function gives an undefined first moment, but first moment still exists?
1d
comment What is the nonlinear estimator for Gaussian Random variable?
What is the question? You know that the best estimator is $E[Y|X=x]$, that is, the mean of the conditional distribution of $Y$ given $X=x$. You know that conditional distribution is Gaussian and you wrote down its mean $\eta_{Y|x}$. What more do you need?
2d
answered Interchange rows in a matrix without using interchange operation
2d
answered Strong Topology and Strong Operator Topology on Hilbert Space
2d
answered Is this identify valid?
2d
comment Why is the mean for the F distribution not 1
If $U$ and $V$ are independent, $E[U/V] = E[U] E[1/V]$. But $E[1/V] \ne 1/E[V]$.
2d
answered Why is the mean for the F distribution not 1
2d
answered “Multivariable” version of this lemma about showing analytically that a number is irrational.
2d
comment Study the convergence of $\int_1^\infty \frac{x\ln x}{x^4-1} dx$
How do you know it's monotonic?
2d
answered Study the convergence of $\int_1^\infty \frac{x\ln x}{x^4-1} dx$
2d
answered False equations with Euler's Identity
2d
comment Evaluate $S=\left|\sum_{n=1}^{\infty} \frac{\sin n}{i^n \cdot n}\right|$
aDo you know series for $\ln(1+z)$?
2d
answered Reversible modular exponent in cryptography
2d
answered Why is a linear autonomous system asymptotically stable iff for all eigenvalues $\lambda$ of $A$, $Re(\lambda) < 0$
2d
answered What is true for rank of a $5\times5$ matrix
2d
comment Diffusion equation problem
Hint: The total amount of heat at time $t$ can be taken to be $\int_0^\ell u(x,t)\; dx$.
2d
comment Diffusion equation problem
The boundaries are insulated, which means $\dfrac{\partial u}{\partial x} =0$ at $x=0$ and $x=\ell$.
2d
answered Show that between any two real roots of the equation $e^x \cos{x}+1=0$, there is a root of the equation $e^x \sin{x}+1=0$
2d
answered Show if $k$ is an integer, then $\sqrt[n]{k}$ is rational if and only if it is an integer.