let L1, L2, L3 be complete LATTICE; for g1 being infs-preserving Function of L1,L2
for g2 being infs-preserving Function of L2,L3 holds LowerAdj (g2 * g1) = (LowerAdj g1) * (LowerAdj g2)
let g1 be infs-preserving Function of L1,L2; for g2 being infs-preserving Function of L2,L3 holds LowerAdj (g2 * g1) = (LowerAdj g1) * (LowerAdj g2)
let g2 be infs-preserving Function of L2,L3; LowerAdj (g2 * g1) = (LowerAdj g1) * (LowerAdj g2)
A1:
[g1,(LowerAdj g1)] is Galois
by Def1;
[g2,(LowerAdj g2)] is Galois
by Def1;
then A2:
[(g2 * g1),((LowerAdj g1) * (LowerAdj g2))] is Galois
by A1, WAYBEL15:5;
g2 * g1 is infs-preserving
by WAYBEL20:25;
hence
LowerAdj (g2 * g1) = (LowerAdj g1) * (LowerAdj g2)
by A2, Def1; verum