reserve T, X, Y for Subset of MC-wff;
reserve p, q, r, s for Element of MC-wff;

theorem Th47:
  ( p => q ) '&' ( p '&' s ) => ( s '&' q ) in IPC-Taut
proof
A1: ( q '&' s ) => ( s '&' q ) in IPC-Taut by Th46;
  ( p => q ) '&' ( p '&' s ) => ( q '&' s ) in IPC-Taut by Th45;
  hence thesis by A1,Th26;
end;
