by wendy » Thu Jan 09, 2020 10:39 am
It's OK. As i was dropping off to sleep, i figured out how this dynkin symbol was indeed a subgroup of {5,3,4}, of order 4.
The Stott matrix should have a positive determinate.
I even played around with a notation for the Gossart tetrahedra, similar to the Schwarz-triangles. It's 3 ordered pairs, where one face appears as the first of each pair, and the remaining faces by one top, two bottom. The odd series are vertices.