961 reputation
512
bio website chemie.uni-hamburg.de/ac/AKs/…
location Hamburg
age 54
visits member for 4 years, 6 months
seen Jun 30 at 15:38
knot theory dilettant!

Jun
24
asked Distiguishing mutant knots
Jun
18
asked Kac-Moody D6 level 2 - “copying” objects necessary for some based rings to categorify?
Jun
17
comment Noncommutative fusion categories
Doesn't matter insofar as I just fell over Haagerup 2 (also called H6) in arxiv1102.2631v2 which I forgot - so we're down to rank 6 anyway.
Jun
17
asked Noncommutative fusion categories
Jun
15
comment Fusion: Hexagon implies pentagon?
EDIT: When I went home, I remembered the obvious (?) standard counterexample: the AxA=1+k*A family. Not a category for k>1 but the S matrix is symmetric and a T with (ST)^3=I exists (only the entries are not cyclotomic).
Jun
14
asked Fusion: Hexagon implies pentagon?
Jun
12
comment Quantum Half :-)
THX! Now I again must look up terms I never heard before but it's a clear mathematical answer :-) (Just another one, is the "halving" unique, i.e. Z(f1)=Z(f2) implies f1=f2?)
Jun
11
asked Quantum Half :-)
Jun
11
comment Fusion categories: If infinity were an integer
So, loosely, a based ring is a category iff it has a consistent (pentagon rule etc.) set of 6j symbols?
Jun
10
comment Fusion categories: If infinity were an integer
Owch! I begin to think that what I always called a "fusion category" is only a "based ring". (I check: Associative, commutative, 1 element, conjugate element. Uhm, can you give me a simple condition for fusion rules or Verlinde matrix that a based ring can be categorified?)
Jun
10
accepted Fusion categories: If infinity were an integer
Jun
9
asked Fusion categories: If infinity were an integer
Jun
2
comment General quantum highest-weights dimension formulas
G2: Some integers cancel out and I possibly use q^3 where I should use q or so :-) (Cf. "GLOBAL DIMENSIONS FOR LIE GROUPS AT LEVEL k AND THEIR CONFORMALLY EXCEPTIONAL QUANTUM SUBGROUPS" by R. Coquereaux, p.23., which was the "next" paper mentioned above. More precise there.) It is not 100% trivial, though, since e.g. i+1 in the A2 formula could translate to [2*i+2]/[2] or [3*i+3]/[3] in quantum integers. Do you have a handy reference to look up the Weyl dimensions of all the simple Lie algebras?
Jun
1
asked General quantum highest-weights dimension formulas
May
29
revised Pseudo-braided fusion categories
Open mouth, insert foot.
May
28
asked Pseudo-braided fusion categories
May
20
comment Fusion category R-symbols diagonal even when multiplicity present?
Also, regarding 3.3. of Galindo: Of course they are, but can you get BOTH Schur and braiding to be diagonal? (I assume the unitary case by default.)
May
20
comment Fusion category R-symbols diagonal even when multiplicity present?
@Matthew - I know the Ostrik paper. But the data is OK - the Verlinde matrix V is symmetric, has V=V+ and VV=I, and it exists a diagonal matrix W such that (VW)^3=I. What is NOT the case is that W is cyclotomic. So F is not modular but still braided. Or do I confuse the many many fusion category bynames again?
May
19
asked Fusion category R-symbols diagonal even when multiplicity present?
May
14
comment Not especially famous, long-open problems which anyone can understand
Arguably, the brick violates the "outside mathematician" condition. I even tried to convince some crank (may one say this word here? :-) not to waste as many of his lifetime to the problem as I did.