reserve E,V for set, G,G1,G2 for _Graph, c,c1,c2 for Cardinal, n for Nat;
reserve f for VColoring of G;
reserve g for EColoring of G;
reserve t for TColoring of G;

theorem Th161:
  c1 c= c2 & G is c1-tcolorable implies G is c2-tcolorable by XBOOLE_1:1;
