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Sage Reference Manual: Elliptic and Plane Curves - Mirrors

Sage Reference Manual: Elliptic and Plane Curves - Mirrors

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<strong>Sage</strong> <strong>Reference</strong> <strong>Manual</strong>: <strong>Elliptic</strong> <strong>and</strong> <strong>Plane</strong> <strong>Curves</strong>, Release 6.1.1sage: <strong>Elliptic</strong>Curve(’37b2’)<strong>Elliptic</strong> Curve defined by y^2 + y = x^3 + x^2 - 1873*x - 31833 over Rational Fieldsage: <strong>Elliptic</strong>Curve(’5077a’)<strong>Elliptic</strong> Curve defined by y^2 + y = x^3 - 7*x + 6 over Rational Fieldsage: <strong>Elliptic</strong>Curve(’389a’)<strong>Elliptic</strong> Curve defined by y^2 + y = x^3 + x^2 - 2*x over Rational FieldOld Cremona labels are allowed:sage: <strong>Elliptic</strong>Curve(’2400FF’)<strong>Elliptic</strong> Curve defined by y^2 = x^3 + x^2 + 2*x + 8 over Rational FieldUnicode labels are allowed:sage: <strong>Elliptic</strong>Curve(u’389a’)<strong>Elliptic</strong> Curve defined by y^2 + y = x^3 + x^2 - 2*x over Rational FieldWe create curves over a finite field as follows:sage: <strong>Elliptic</strong>Curve([GF(5)(0),0,1,-1,0])<strong>Elliptic</strong> Curve defined by y^2 + y = x^3 + 4*x over Finite Field of size 5sage: <strong>Elliptic</strong>Curve(GF(5), [0, 0,1,-1,0])<strong>Elliptic</strong> Curve defined by y^2 + y = x^3 + 4*x over Finite Field of size 5<strong>Elliptic</strong> curves over Z/NZ with N prime are of type “elliptic curve over a finite field”:sage: F = Zmod(101)sage: <strong>Elliptic</strong>Curve(F, [2, 3])<strong>Elliptic</strong> Curve defined by y^2 = x^3 + 2*x + 3 over Ring of integers modulo 101sage: E = <strong>Elliptic</strong>Curve([F(2), F(3)])sage: type(E)sage: E.category()Category of schemes over Ring of integers modulo 101In contrast, elliptic curves over Z/NZ with N composite are of type “generic elliptic curve”:sage: F = Zmod(95)sage: <strong>Elliptic</strong>Curve(F, [2, 3])<strong>Elliptic</strong> Curve defined by y^2 = x^3 + 2*x + 3 over Ring of integers modulo 95sage: E = <strong>Elliptic</strong>Curve([F(2), F(3)])sage: type(E)sage: E.category()Category of schemes over Ring of integers modulo 95The following is a curve over the complex numbers:sage: E = <strong>Elliptic</strong>Curve(CC, [0,0,1,-1,0])sage: E<strong>Elliptic</strong> Curve defined by y^2 + 1.00000000000000*y = x^3 + (-1.00000000000000)*x over Complex Fisage: E.j_invariant()2988.97297297297We can also create elliptic curves by giving the Weierstrass equation:sage: x, y = var(’x,y’)sage: <strong>Elliptic</strong>Curve(y^2 + y == x^3 + x - 9)<strong>Elliptic</strong> Curve defined by y^2 + y = x^3 + x - 9 over Rational Field42 Chapter 10. <strong>Elliptic</strong> curve constructor

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