
theorem
  xor3.<*0,0,0*> = 0 & xor3.<*0,0,1*> = 1 & xor3.<*0,1,0*> = 1 & xor3.<*
  0,1,1*> = 0 & xor3.<*1,0,0*> = 1 & xor3.<*1,0,1*> = 0 & xor3.<*1,1,0*> = 0 &
  xor3.<*1,1,1*> = 1
proof
  thus xor3.<*0,0,0*> = FALSE 'xor' FALSE by Def20
    .= 0;
  thus xor3.<*0,0,1*> = FALSE 'xor' FALSE 'xor' TRUE by Def20
    .= 1;
  thus xor3.<*0,1,0*> = 1 by Def20,BINARITH:13;
  thus xor3.<*0,1,1*> = TRUE 'xor' TRUE by Def20,BINARITH:13
    .= 0;
  thus xor3.<*1,0,0*> = 1 by Def20,BINARITH:13;
  thus xor3.<*1,0,1*> = TRUE 'xor' TRUE by Def20,BINARITH:13
    .= 0;
  thus xor3.<*1,1,0*> = TRUE 'xor' TRUE 'xor' FALSE by Def20
    .= 0;
  thus xor3.<*1,1,1*> = TRUE 'xor' TRUE 'xor' TRUE by Def20
    .= 1;
end;
