A classification of invertible subsets of affine root systems

✍ Scribed by P. Check; C. Kriloff; D.R. Stephenson

• Book ID: 104152916
• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 650 KB
• Volume: 131
• Category: Article
• ISSN: 0022-4049
• DOI: 10.1016/s0022-4049(97)00081-9

✦ Synopsis

All subsets P of an irreducible affine root system R such that P and R\P arc closed under addition of roots are classified. It is shown that if II: R + R' is a bijection of root systems such that 1) and 0-l preserve closed sets and the irreducible components of R and R' arc afine or finite with at most one irreducible component of type A, then (I is an isomorphism of root systems.