reserve X for BCI-algebra;
reserve x,y,z for Element of X;
reserve i,j,k,l,m,n for Nat;
reserve f,g for sequence of the carrier of X;

theorem Th26:
  max(i,j,m,n) >= i & max(i,j,m,n) >= j & max(i,j,m,n) >= m & max(
  i,j,m,n) >= n
proof
A1: max(m,n) >= m & max(m,n) >= n by XXREAL_0:25;
A2: max(i,j,m,n) >= max(i,j) & max(i,j,m,n) >= max(m,n) by XXREAL_0:25;
  max(i,j) >= i & max(i,j) >= j by XXREAL_0:25;
  hence thesis by A1,A2,XXREAL_0:2;
end;
