theorem Th54: :: EC_PF_2:54

for p being 5 _or_greater Prime
for z being Element of EC_WParam p
for g2, gf1, gf2, gf3 being Element of (GF p)
for P, Q being Element of EC_SetProjCo ((z `1),(z `2),p)
for R being Element of [: the carrier of (GF p), the carrier of (GF p), the carrier of (GF p):] st g2 = 2 mod p & gf1 = ((Q `2_3) * (P `3_3)) - ((P `2_3) * (Q `3_3)) & gf2 = ((Q `1_3) * (P `3_3)) - ((P `1_3) * (Q `3_3)) & gf3 = ((((gf1 |^ 2) * (P `3_3)) * (Q `3_3)) - (gf2 |^ 3)) - (((g2 * (gf2 |^ 2)) * (P `1_3)) * (Q `3_3)) & R = [(gf2 * gf3),((gf1 * ((((gf2 |^ 2) * (P `1_3)) * (Q `3_3)) - gf3)) - (((gf2 |^ 3) * (P `2_3)) * (Q `3_3))),(((gf2 |^ 3) * (P `3_3)) * (Q `3_3))] holds
(gf2 * (P `3_3)) * (R `2_3) = - ((gf1 * (((R `1_3) * (P `3_3)) - ((P `1_3) * (R `3_3)))) + ((gf2 * (P `2_3)) * (R `3_3)))