Virasoro 1970: central extension of Witt algebra [L_m, L_n] = (m-n) L_{m+n} + c/12 (m^3 - m) delta_{m+n,0}; central charge c labels universality class; 2D CFT generators.
Virasoro 1970: central extension of Witt algebra [L_m, L_n] = (m-n) L_{m+n} + c/12 (m^3 - m) delta_{m+n,0}; central charge c labels universality class; 2D CFT generators.