Robert Garbary, Pure Mathematics, University of Waterloo
"Coherence and O(1)"
On an affine scheme Spec(R), a coherent sheaf is a sheaf that 'comes from a module' over R. In the case where S is a ($\mathbb{Z}$-)graded ring, we may construct a graded S-module out of S by 'twisting' the grading. This sheaf (over Proj(S)) is called O(1). I will go over some non-examples of coherence, and go over the construction and basic properties of O(1).