Description

Commutative Algebra seminar.

Speaker: R V Gurjar.

Affiliation: IIT Bombay.

Date and Time: Monday 30 September, 3:30 pm - 5:00 pm.

Venue: Room 215, Department of Mathematics.

Title: P. Samuel's descent theorem.

Abstract: Let R be a normal noetherian domain with a finite group of

automorphisms G. Samuel's result says that the kernel of the natural

homomorphism Cl(R^G)\to Cl(R) is a subgroup of H^1(G,U), where U is the

group of units in R.

If R is divisorially unramified over R^G then the kernel is isomorphic to

H^1(G,U). This enables us to find the divisor class groups of rings of

invariants of finite group actions on polynomial or power series rings. If

time permits two general constructions of cyclic unramified coverings of

normal varieties will be discussed.

Speaker: R V Gurjar.

Affiliation: IIT Bombay.

Date and Time: Monday 30 September, 3:30 pm - 5:00 pm.

Venue: Room 215, Department of Mathematics.

Title: P. Samuel's descent theorem.

Abstract: Let R be a normal noetherian domain with a finite group of

automorphisms G. Samuel's result says that the kernel of the natural

homomorphism Cl(R^G)\to Cl(R) is a subgroup of H^1(G,U), where U is the

group of units in R.

If R is divisorially unramified over R^G then the kernel is isomorphic to

H^1(G,U). This enables us to find the divisor class groups of rings of

invariants of finite group actions on polynomial or power series rings. If

time permits two general constructions of cyclic unramified coverings of

normal varieties will be discussed.

Description

Room No. 215 Department of Mathematics

Date

Mon, September 30, 2019

Start Time

3:30pm-5:00pm IST

Duration

1 hour 30 minutes

Priority

5-Medium

Access

Public

Created by

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Updated

Mon, September 30, 2019 11:45am IST