feynlag.groups.discrete

Discrete symmetries: Z_N and S_3 (extensible to other finite groups).

A discrete group needs only (a) irrep labels with finite generator matrices and (b) the assignment of field multiplets to irreps. Invariance of a term under the whole group is equivalent to invariance under the generators.

Multiplets may span several Field objects — e.g. an S₃ doublet of Higgs SU(2) doublets (H1, H2): the generator mixes the two fields component-by-component (each gauge component transforms in parallel).

Classes

DiscreteSymmetry(name)	Base class: irreps defined by generator matrices.
S3([name])	The permutation group S₃ with irreps '1', '1p', '2'.
ZN(name, N)	Cyclic group Z_N: irrep k acts as φ → ω^k φ, ω = e^{2πi/N}.