theorem Th26:
  1 to_power a = 1
proof
A1: 1 #R a <> 0 by PREPOWER:81;
  thus
  1 to_power a = (1/1) #R a by Def2
    .= (1 #R a) / (1 #R a) by PREPOWER:80
    .= 1 by A1,XCMPLX_1:60;
end;
