SHEAVES ON SPACES Contents

SHEAVES ON SPACES Contents

DIVISORS ON ALGEBRAIC SPACES Contents

For some reason it seem convenient to define the notion of an effective Cartier divisor before anything else. Note that in Morphisms of Spaces, Section 13 we discussed the correspondence between closed subspaces and quasi-coherent sheaves of ideals. Moreover, in Properties of Spaces, Section 28, we discussed properties of quasi-coherent modules, in particular “locally generated by 1 element”. T...

DIVISORS ON ALGEBRAIC SPACES Contents

For some reason it seem convenient to define the notion of an effective Cartier divisor before anything else. Note that in Morphisms of Spaces, Section 13 we discussed the correspondence between closed subspaces and quasi-coherent sheaves of ideals. Moreover, in Properties of Spaces, Section 28, we discussed properties of quasi-coherent modules, in particular “locally generated by 1 element”. T...

Instanton sheaves on complex projective spaces

We study a class of torsion-free sheaves on complex projective spaces which generalize the much studied mathematical instanton bundles. Instanton sheaves can be obtained as cohomologies of linear monads and are shown to be semistable if its rank is not too large, while semistable torsion-free sheaves satisfying certain cohomological conditions are instanton. We also study a few examples of modu...

Perverse Coherent Sheaves on Blow-up. Ii. Wall-crossing and Betti Numbers Formula

This is the second of series of papers studyig moduli spaces of a certain class of coherent sheaves, which we call stable perverse coherent sheaves, on the blow-up p : X̂ → X of a projective surface X at a point 0. The followings are main results of this paper: a) We describe the wall-crossing between moduli spaces caused by twisting of the line bundle O(C) associated with the exceptional diviso...