reserve R,R1 for commutative Ring;
reserve A,B for non degenerated commutative Ring;
reserve o,o1,o2 for object;
reserve r,r1,r2 for Element of R;
reserve a,a1,a2,b,b1 for Element of A;
reserve f for Function of R, R1;
reserve p for Element of Spectrum A;

theorem Th1:
  0.A is Zero_Divisor of A
  proof
    consider b be Element of A such that
A1: b = 1.A;
    0.A * b = 0.A; then
    0.A is zero_divisible by A1;
    hence thesis;
  end;
