14,979 reputation
13982
bio website zakuski.math.utsa.edu/~jagy
location Berkeley, California
age 58
visits member for 4 years, 11 months
seen 4 hours ago
My main activity is in number theory of integral positive ternary quadratic forms. This began through years of working with Irving Kaplansky. Much of his unpublished writing on quadratic forms can be found as pdfs at http://zakuski.math.utsa.edu/~kap/forms.html and about Lie and Jordan superalgebras at http://zakuski.math.utsa.edu/~kap/superalgebra.html One of my own email addresses can be found easily using the search feature at http://www.ams.org/cml and just putting in my last name

Dec
24
comment Ruth-Aaron triples, etc
@BenjaminDickman, thanks.
Dec
24
comment Ruth-Aaron triples, etc
Did Erdos ever meet either Ruth or Aaron?
Dec
17
comment intuitive interpretation of analytic spread
Yes, I also find it very difficult.
Dec
8
comment Why do Pell equations appear in Ramanujan's pi formulas?
also 5280...........
Dec
8
comment Why do Pell equations appear in Ramanujan's pi formulas?
number 640320 on page 462
Dec
8
comment Why do Pell equations appear in Ramanujan's pi formulas?
Igor, got to be this: archive.org/stream/lehrbuchderalgeb03webeuoft#page/n17/mode/2up
Dec
8
comment Why do Pell equations appear in Ramanujan's pi formulas?
one of two three-volume sets, maybe separate, maybe the same: en.wikipedia.org/wiki/Heinrich_Martin_Weber
Dec
6
comment Help solving a recurrence relation
required by whom?
Dec
5
comment Orthogonal mud cracks and Maxwell's reciprocal figures
On the other item, orthogonal families are a common item, more or less the stereographic projection of latitude and longitude circles on the sphere to the plane.
Dec
5
comment Orthogonal mud cracks and Maxwell's reciprocal figures
I understood it was a matter of minimizing energy during the creation of each new crack. There ought to be plausible explanations in both geology and materials science texts.
Nov
27
comment Equitably distributed curve on a sphere
about existence, not worried, see en.wikipedia.org/wiki/Knot_energy We can replace the ambient distance by geodesic distance. Likely the winner for your picture length is the laces on a baseball; i would expect to be able to prove smoothness of the optimizer. As usual, Rob Kusner has written about closely related things.
Nov
23
awarded  Popular Question
Nov
23
revised Realizing proper pure octonions as conjugates
deleted 2 characters in body; edited title
Nov
15
comment Every free abelian group is slender, why?
@TheMaskedAvenger, also Yemon asked me to post it as an answer. Note that Alexander and Irina are probably slightly different people, but likely relatives.
Nov
15
comment Every free abelian group is slender, why?
@AlexanderGelbukh, would you prefer that people not contribute what they have? I expect your kind of reaction on MSE, where most questions are homework and people complain if they cannot turn in an answer word for word as their own work.
Nov
15
answered Every free abelian group is slender, why?
Nov
15
comment Every free abelian group is slender, why?
@Yemon, alright.
Nov
15
comment Every free abelian group is slender, why?
the short paper by Nunke is available; it appears everything relevant happened from the late 1950's to the early 1960's, various authors projecteuclid.org/euclid.bams/1183524151
Nov
13
comment Frobenius density theorem
@IgorRivin, the other direction, if a prime that does not divide the discriminant factors the polynomial mod p into a certain partition of irreducible factor degrees, then the Galois group must have an element with such cycle structure, is often called Dedekind's Theorem and is in, for example, Galois Theory by David A. Cox, second edition 2012. This is the direction one is using when factoring mod p for several primes and drawing conclusions about the Galois group.
Nov
13
comment How many Pythagorean triples are there in which every member is triangular?
@JeremyRouse, anyway, I can make a tag if you like, your best fairly short phrasing.