Speaker: 
Ian Jack
Speaker affiliation: 
Liverpool
Date: 
Friday, February 2, 2018 - 13:00
Room: 
Seminar Room
Title: 
The a-theorem, scheme invariants and Hopf algebras
Abstract: 
We show how the existence of an a-theorem imposes constraints on the beta-functions which may be expressed in terms of renormalisation-scheme-invariant combinations of the beta-function coefficients. This motivates a general discussion of scheme-invariance; we show that the structure of scheme transformations implies significantly more scheme-invariants than might be naively expected. Finally we show that the language of Hopf algebras provides a convenient means to describe the requirements of scheme invariance.