EllPoint - EllPoint -- a unary or binary operator, usually used for negation or subtraction

i1 : E=ellCurve(3,8,GF(13))

o1 = Elliptic Curve defined by Y^2 = X^3 + 3 X + (-5) over (GF 13).

o1 : EllipticCurve

i2 : P=ellPoint({1,5,1},E)

o2 = Point  {1, 5, 1}  on the (Elliptic Curve defined by Y^2 = X^3 + 3 X + (-5) over (GF 13).)

o2 : EllPoint

i3 : Q=ellPoint({2,3,1},E)

o3 = Point  {2, 3, 1}  on the (Elliptic Curve defined by Y^2 = X^3 + 3 X + (-5) over (GF 13).)

o3 : EllPoint

i4 : P-Q

o4 = Point  {-4, -6, 1}  on the (Elliptic Curve defined by Y^2 = X^3 + 3 X + (-5) over (GF 13).)

o4 : EllPoint