Quantum groups acting on 4 points
Quantum groups acting on 4 points
We classify the compact quantum groups acting on 4 points. These are the quantum subgroups of the quantum permutation group ๐ 4. Our main tool is a new presentation for the algebra C(๐ 4), corresponding to an isomorphism of type ๐ 4 โ SOโ1(3). The quantum subgroups of ๐ 4 are subject to a โฆ