reserve n, k, r, m, i, j for Nat;

theorem Th36:
  - 1 / tau = tau_bar
proof
A1: 1 - sqrt 5 <> 0 by SQUARE_1:20,27;
  - 1 / tau = -1 * (2 / (1 + sqrt 5)) by FIB_NUM:def 1,XCMPLX_1:57
    .= -1 * ((2 * (1 - sqrt 5)) / ((1 + sqrt 5) * (1 - sqrt 5))) by A1,
XCMPLX_1:91
    .= -1 * ((2 * (1 - sqrt 5)) / (1 - (sqrt 5) ^2))
    .= -1 * ((2 * (1 - sqrt 5)) / (1 - 5)) by SQUARE_1:def 2
    .= (1 - sqrt 5) / 2;
  hence thesis by FIB_NUM:def 2;
end;
