Journal of Lie Theory Vol. 12, No. 2, pp. 515527 (2002) 

Extended Affine Root SystemsSaeid AzamSaeid AzamDepartment of Mathematics University of Isfahan Isfahan, Iran P.O.Box 81745 and Institute for Studies in Theoretical Physics and Mathematics (IPM) saeidazam@yahoo.com Abstract: There are two notions of the extended affine root systems in the literature which both are introduced axiomatically. One, extended affine root system (SAERS for short), consists only of nonisotropic roots, while the other, extended affine root system (EARS for short), contains certain isotropic roots too. We show that there is a one to one correspondence between (reduced) SEARSs and EARSs. Namely the set of nonisotropic roots of any EARS is a (reduced) SEARS, and conversely, there is a unique way of adding certain isotropic elements to a SEARS to get an EARS. (It is known that some of extended affine root systems are not the root system of any extended affine Lie algebra.) Every article should have an abstract. Full text of the article:
Electronic fulltext finalized on: 6 May 2002. This page was last modified: 21 May 2002.
© 2002 Heldermann Verlag
