Robert Israel

Vancouver BC

http://www.math.ubc.ca/~israel

Associate Professor Emeritus, University of British Columbia, and Optimization Algorithms Researcher, D-Wave Systems, Burnaby BC

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$\frac{1}{n}$ as a difference of Egyptian fractions with all denominators $<n$

number-theory elementary-number-theory egyptian-fractions asked Nov 24, 2016 at 18:55

math.stackexchange.com

42 votes

Fibonacci $\equiv -1 \mod p^2$

number-theory elementary-number-theory prime-numbers modular-arithmetic fibonacci-numbers asked Jul 17, 2015 at 23:33

math.stackexchange.com

36 votes

$3 \times 3$ matrix with determinant a large power of $2$

linear-algebra matrices elementary-number-theory determinant asked Jul 7, 2020 at 19:47

math.stackexchange.com

34 votes

A remarkable almost-identity

nt.number-theory ca.classical-analysis-and-odes sequences-and-series integer-sequences polylogarithms asked Sep 5, 2018 at 20:28

mathoverflow.net

22 votes

Embedding as a subgroup

group-theory algorithms gap magma-cas asked Apr 23, 2014 at 23:02

math.stackexchange.com

20 votes

Primes in solutions to Pell-type equations

number-theory elementary-number-theory pell-type-equations asked Dec 24, 2020 at 20:27

math.stackexchange.com

16 votes

$p^2 - 2 q^2 = 5039$ for primes $p, q$

number-theory elementary-number-theory diophantine-equations asked Jun 26, 2019 at 3:10

math.stackexchange.com

14 votes

Probability of coprime polynomials

nt.number-theory polynomials finite-fields pr.probability asked Oct 24, 2013 at 16:08

mathoverflow.net

14 votes

Diophantine equation $(x+y)(x+y+1) - kxy = 0$

number-theory elementary-number-theory diophantine-equations vieta-jumping asked Sep 1, 2015 at 18:36

math.stackexchange.com

14 votes

$x^4 + y^4 \mod p$

number-theory elementary-number-theory asked Jul 10, 2017 at 1:14

math.stackexchange.com

Top Answers

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mathoverflow.net

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1, 5, 9, 13, 17, 21,...

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What, fundamentally, is the reason for the shape of a sin curve?

math.stackexchange.com

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Robert Israel

$\frac{1}{n}$ as a difference of Egyptian fractions with all denominators $<n$

Fibonacci $\equiv -1 \mod p^2$

$3 \times 3$ matrix with determinant a large power of $2$

A remarkable almost-identity

Embedding as a subgroup

Primes in solutions to Pell-type equations

$p^2 - 2 q^2 = 5039$ for primes $p, q$

Probability of coprime polynomials

Diophantine equation $(x+y)(x+y+1) - kxy = 0$

$x^4 + y^4 \mod p$