reserve w, w1, w2 for Element of ExtREAL;
reserve c, c1, c2 for Complex;
reserve A, B, C, D for complex-membered set;
reserve F, G, H, I for ext-real-membered set;
reserve a, b, s, t, z for Complex;
reserve f, g, h, i, j for ExtReal;
reserve r for Real;
reserve e for set;

theorem Th102:
  f in F & g in G implies f/g in F///G
proof
A1: f in ExtREAL & g in ExtREAL by XXREAL_0:def 1;
  F///G = {w1/w2: w1 in F & w2 in G} by Th101;
  hence thesis by A1;
end;
