Lemma 8.11, Case 2 and the statement #
Case 2 of lem:opposite-controls (local-ray-geometry.tex): fg = 0 with
f q², q² g ≠ 0 is excluded by the seven-object category with arrows
u → c → d, u → u', l → c → r, l_d → d and the relation l → c → r = 0
(dimensions 3 at c, 2 at u, d, 1 elsewhere: N = 22, D = 21, F = 1).
Indices 0..6 are u' u c d l r l_d.
The table of the seven-object category.
Instances For
The objects.
Instances For
The weights.
Instances For
The rays.
Instances For
The seven-object category of Case 2 is excluded.
g q_a^j ∈ R_c q² g for j ≥ 1.
A loop equal to q^m e and to q forces m = 1.
Lemma 8.11(1) (lem:opposite-controls): for generating f : b → c, g : c → a
whose Homs are cyclic at c but not at the other endpoints, f q² = 0 or q² g = 0.
Lemma 8.11(2), first part: f q^n g = 0 for n ≥ 2.
Lemma 8.11(2), socle part: the source radical kills f q^n g.
Lemma 8.11(2), socle part: the target radical kills f q^n g.