reserve x for set;
reserve i,j for Integer;
reserve n,n1,n2,n3 for Nat;
reserve p for Prime;
reserve a,b,c,d for Element of GF(p);
reserve K for Ring;
reserve a1,a2,a3,a4,a5,a6 for Element of K;

theorem Th30:
  for p be 5_or_greater Prime,
  z be Element of EC_WParam p holds
  p > 3 & Disc(z`1,z`2,p) <> 0.GF(p)
  proof
    let p be 5_or_greater Prime,
    z be Element of EC_WParam p;
    p >= 4+1 by Def1;
    hence p > 3 by XXREAL_0:2;
    z in {[a,b] where a,b is Element of GF(p) :
    Disc(a,b,p) <> 0.GF(p) }; then
    consider a,b be Element of GF(p) such that
    A1: z = [a,b] & Disc(a,b,p) <> 0.GF(p);
    thus Disc(z`1,z`2,p) <> 0.GF(p) by A1;
  end;
