University of Calgary

Valuations, Newton Polygons, and an Eisenstein Criterion for Ordinary Linear Differential Operators

Submitted by ppaterso on Mon, 08/10/2009 - 3:15pm.
Aug 17 2009 - 2:00pm
Aug 17 2009 - 3:00pm
Speaker: 

Rick Churchill

Professor of Mathematics, Hunter College and the Graduate Center of CUNY (The City University of New York) 

Adjunct Professor of Mathematics, University of Calgary

Location: 
MS 431
Number Theory/Applied Math Talk
Eisenstein's criterion is a classical irreducibility test for polynomials in Z[x].  One of the first applications  encountered in number theory is a proof of the irreducibility of the p^th cyclotomic polynomial for any rational integer prime p.  In this talk we cast the proof in geometric terms and use that approach to generalize the result to skew-polynomials, which include ordinary linear differential operators.

The talk is aimed at an elementary level, and prior acquaintance with valuations and/or Newton polygons is not assumed.  Technical details will be kept to a minimum.

The results cover a portion of recent joint work of the speaker and Yang
Zhang of the University of Manitoba.