The Department of Mathematics & Statistics invites students, faculty, and staff to attend the upcoming colloquium with speaker Dr. Basil Nanayakkara on Thursday, July 2nd, from 2:00 PM to 3:00 PM in MCJ 404. The talk is entitled Zariski cotangent space.
Abstract
In algebraic geometry, a scheme is an ordered pair (X, O_X) where X is a topological space and O_X is a sheaf of commutative rings on X such that each point p in X has a neighbourhood that is isomorphic to (specA, O_A) where specA is the prime spectrum of a commutative ring A and O_A is the sheaf on specA induced by the ring structure of A. It was Oscar Zariski who defined the cotangent space to X at p to be m_p/m_p^2 where m_p is the unique maximal ideal of the stalk O_{X,p} of the sheaf O_X at p. We will show that this is a sensible definition by constructing an isomorphism between the dual (m_p/m_p^2)* with the tangent space to a smooth manifold at a point as defined in differential geometry. We will show further that this isomorphism is natural (in the sense of category theory).

