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Abstract

Let Md be the moduli space of algebraic maps (morphisms) of degree d from [special characters omitted] to a fixed Grassmannian. The main purpose of this thesis is to provide an explicit construction of a compactification of Md satisfying the following property: the compactification is a smooth projective variety and the boundary is a simple normal crossing divisor. The main tool of the construction is blowing-up. We start with a smooth compactification given by Quot scheme, which we denote by Qd. The boundary Qd \ Md is singular and of high codimension. Next, we give a filtration of the boundary Qd \ Md by closed subschemes: Zd,0Z d,1 ⊂ ··· Z d,d–1 = Qd \ Md. Then we blow up the Quot scheme Qd along these subschemes succesively, and prove that the final outcome is a compactification satisfying the desired properties. The proof is based on the key observation that each Zd,r has a smooth projective variety which maps birationally onto it. This smooth projective variety, denoted by Qd,r, is a relative Quot scheme over the Quot-scheme compactification Qr for Mr. The map from Qd,r to Zd,r is an isomorphism when restricted to the preimage of Zd,r \ Zd,r –1. With the help of the Qd,r's, one can show that the final outcome of the successive blowing-up is a smooth compactification whose boundary is a simple normal crossing divisor.

Details

Title
A compactification of the space of algebraic maps from P1 to a Grassmannian
Author
Shao, Yijun
Year
2010
Publisher
ProQuest Dissertations & Theses
ISBN
978-1-124-25629-0
Source type
Dissertation or Thesis
Language of publication
English
ProQuest document ID
759814139
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.