Per Alexandersson

Zurich, Switzerland

www2.math.su.se/~per

Age: 28

Currently interested in Schur functions, key Polynomials and semistandard Young tableaux and misc. related representation theory and combinatorics.

Phd thesis defended 2013, titled Combinatorial Methods in Complex Analysis.

I keep an eye out for interesting results related to complex dynamics, computability, and computer-assisted research. I use Mathematica extensively in my research. My other main programming languages are Java, LaTeX, PHP, C, etc.

Oh, and I like generative art.

18h
comment Smallest integer $k$ so that no Sudoku grid has exactly $k$ solutions
according to wikipedia, the blank sudoku allows 6,670,903,752,021,072,936,960 number of solutions, so the number we seek is less than that :P. Also, I guess this implies that there is no sudoku that admits exactly 6,670,903,752,021,072,936,959 solutions :D
22h
comment Smallest integer $k$ so that no Sudoku grid has exactly $k$ solutions
@Mauris: Sure, i added it now. its pretty basic, but less complicated means fewer bugs usually.
22h
revised Smallest integer $k$ so that no Sudoku grid has exactly $k$ solutions
added 1396 characters in body
22h
awarded Nice Question
1d
awarded Peer Pressure
2d
comment From thesis text to slides. How to ease the process?
Yeah, don't copy-paste from the thesis, except maybe math environment stuff. It will be very dry/too quick otherwise. Better, examples and pictures should be more abundant in a presentation, as well as motivation and general ideas.
2d
asked Finding combinatorial models / statistics
2d
comment convex hull of the set of permutations with one cycle
Hm, you mean similar to the Birkhoff polytope, as a nice list of inequalities and equalities? en.wikipedia.org/wiki/Birkhoff_polytope
2d
reviewed Approve suggested edit on Why should we care about "higher infinities" outside of set theory?
2d
comment Permutations of given length
This is undergraduate level combinatorics, I suggest to migrate question to stackexchange instead.
2d
comment Permutations of given length
This is undergraduate level combinatorics, I suggest to migrate question to stackexchange instead.
Aug
26
comment Who to invite to as a speaker?
People known for giving good talks is a good metric, especially for colloquiums.
Aug
26
comment What is a "good" PhD dropout rate, and how would we know?
Where I went in Sweden, any dropout is a serious matter, that should be avoided if possible. If a student is too weak to not complete the program, he/she should not have been admitted in the first place, as it wastes both the institution and the students time. Of course, there are other, unforeseen circumstances (personal tragedies), but these are of course something that are extraordinary as well.
Aug
26
awarded Revival
Aug
25
revised Is this an instance of any existing convex pentagonal tilings?
added 71 characters in body
Aug
25
comment Is this an instance of any existing convex pentagonal tilings?
@YoavKallus: Ah, you are right!
Aug
25
reviewed Approve suggested edit on Generators for SL_2(R) for rings of integers R
Aug
25
comment Is this an instance of any existing convex pentagonal tilings?
Added: According to this source, jaapsch.net/tilings/Tilings.pdf all 1-isohedral tilings are fully understood....
Aug
25
comment Is this an instance of any existing convex pentagonal tilings?
Yeah, it seems so simple, that it is most likely in the original family of 5, since it has the 1-isohedral property, and these are probably easy to exhaust/verify is complete by computer search (but I might be completely wrong on this, maybe suitable as a follow-up question?).
Aug
25
answered Is this an instance of any existing convex pentagonal tilings?
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