970 reputation
513
bio website chemie.uni-hamburg.de/ac/AKs/…
location Hamburg
age 54
visits member for 4 years, 7 months
seen Jul 26 at 13:42
knot theory dilettant!

Jul
15
revised Quadratic Casimirs of the E7 series
And a typo. Sigh...
Jul
15
revised Quadratic Casimirs of the E7 series
Argl. Example wasn't formulated precisely enough.
Jul
15
revised Quadratic Casimirs of the E7 series
example given
Jul
15
asked Quadratic Casimirs of the E7 series
Jul
8
awarded  Popular Question
Jun
24
asked Distiguishing mutant knots
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
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.