I guess g
stands for "the" generator of the Field F(2^4)
.
You can get the documentation about the ways to construct elliptic curves by typing:
sage: EllipticCurve?
Then you can try something along the lines:
sage: F = GF(2^4, 'g') ; F
Finite Field in g of size 2^4
sage: F.inject_variables()
Defining g
sage: R.<x,y> = F[] ; R
Multivariate Polynomial Ring in x, y over Finite Field in g of size 2^4
sage: C = EllipticCurve(y^2+x*y-x^3-g^3*x^2-(g^3+1)) ; C
Elliptic Curve defined by y^2 + x*y = x^3 + g^3*x^2 + (g^3+1) over Finite Field in g of size 2^4