--- created: 2024-04-28T13:11 updated: 2024-04-28T13:11 --- # Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville > [!WARNING] **Do not modify** this file > This file is automatically generated by scrybble and will be overwritten whenever this file in synchronized. > Treat it as a reference. ## Pages ### [[Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville.pdf#page=7|Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville, page 7]] > ruled surfaces, that is, surfaces birational to lP x C. > their minimal models are Pl-bundles over a base curve C, > (the Veronese surface, del Pezzo surfaces, ### [[Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville.pdf#page=8|Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville, page 8]] > p9 = 0 and q > 2 is ruled; > Thus a surface is ruled if and only if P12 = 0 (Enriques' theorem). ### [[Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville.pdf#page=11|Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville, page 11]] > If f is surjective, > f * Ox (D) = Os (f * (D)) ### [[Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville.pdf#page=12|Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville, page 12]] > f. f * D = dD for all divisors D on S > m.,(C fl C') = 1 if and only if f and g generate the maximal ideal ,;, i.e. form a system of local coordinates in a neighbourhood of x : C and C' are then said to be transverse at x. ### [[Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville.pdf#page=13|Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville, page 13]] > deg(Llc) ### [[Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville.pdf#page=14|Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville, page 14]] > g*D.g*D' = d(D.D'). ### [[Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville.pdf#page=15|Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville, page 15]] ### [[Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville.pdf#page=16|Complex Algebraic Surfaces, 2nd ed_ - Arnaud Beauville, page 16]] > T = H1(S, Os)/H1(S, Z) > that H'(S,Z) is a lattice in H'(S, Os), so T has a natural structure of complex torus);