143,670 reputation
592238
bio website math.ubc.ca/~israel
location Richmond, Canada
age
visits member for 3 years, 9 months
seen 1 hour ago

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


2h
answered Expectation of 1/Y. Y~Gam
2h
answered Maple: How do I type “solve” with an arrow under?
3h
comment Arithmetic functions of particular type
For example, the sum of the primes $\le x$?
7h
answered Explanation of Proof for (Dis)continuity of Thomae's Function
18h
comment Find the sum of digits of m?
This is not a matter of checking. It is finding the condition for a number $z$ to be expressible in this way in terms of the congruence class of $z \mod 4$.
18h
revised Diophantine equation : two products of linear factors differ by a constant
added 263 characters in body
19h
answered Find the sum of digits of m?
20h
answered Diophantine equation : two products of linear factors differ by a constant
21h
comment Diophantine equation : two products of linear factors differ by a constant
Certainly it can't be "only a few", because if $p(X) = (X-a)(X-b)(X-c)$ is a solution (for a given $k$), then so is $p(X + m)$ for any integer $m$. So either no solutions or infinitely many.
2d
comment Are the poll results likely to be valid if they are based on only those subjects who agree to respond?
There was a time when having Gallup call you up and ask your opinion was a novelty, and people were happy to participate. Now it's just an annoyance. Why should I provide valuable data to a commercial enterprise for free?
2d
comment Determining a radius convergence of a power series
Differentiate term-by-term...
2d
comment sum of infinte series with exponential and factorial terms
There is probably no closed form for the sum (when it converges). What do you really need?
2d
comment Is the simplest form of a quadratic equation factored form or standard form?
Simplicity, like beauty, is in the eye of the beholder.
2d
answered A question about sum of n random variables
2d
comment Why does the set of an hermitian operator's eigenfunctions spans the functions space
Actually, physical applications tend to deal with unbounded self-adjoint operators.
2d
answered Why does the set of an hermitian operator's eigenfunctions spans the functions space
2d
answered Limit of arc-length of a curve
2d
comment Should I Put My Lifesavings into the Lottery?
See en.wikipedia.org/wiki/Utility
2d
comment What is the “cost” of computation of two special CAS algorithms
en.wikipedia.org/wiki/…
2d
comment Is there a formula telling if number is prime?
What is the difference for you between a function and an algorithm?