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Tom Halverson

Publications and source records attributed to Tom Halverson.

21 records · Page 2Linked to original sources
arXiv2004

Partition Algebras

The partition algebras are algebras of diagrams (which contain the group algebra of the symmetric group and the Brauer algebra) such that the multiplication is given by a combinatorial rule and such that the structure constants of the algebra depend polynomially on a parameter. This is a survey paper which proves the primary results in the theory of partition algebras. Some of the results in this paper are new. This paper gives: (a) a presentation of the partition algebras by generators and relations, (b) shows that each partition algebra has an ideal which is isomorphic to a basic construction and such that the quotient is isomorphic to the group algebra of the symmetric gropup, (c) shows that partition algebras are in "Schur-Weyl duality" with the symmetric groups on tensor space, (d) provides a construction of "Specht modules" for the partition algebras (integral lattices in the generic irreducible modules), (e) determines (with a couple of exceptions) the values of the parameter where the partition algebras are semisimple, (f) provides "Murphy elements" for the partition algebras that play exactly analogous roles to the classical Murphy elements for the group algebra of the symmetric group. The primary new results in this paper are (a) and (f).

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arXiv1995

Murnaghan-Nakayama rules for characters of Iwahori-Hecke algebras of the complex reflection groups G(r,p,n)

Iwahori-Hecke algebras for the infinite series of complex reflection groups $G(r,p,n)$ were constructed recently in the work of Ariki and Koike, Broué and Malle, and Ariki. In this paper we give Murnaghan-Nakayama type formulas for computing the irreducible characters of these algebras. Our method is a generalization of that in our earlier paper in which we derived Murnaghan-Nakayama rules for the characters of the Iwahori-Hecke algebras of the classical Weyl groups. In both papers we have been motivated by C. Greene, who gave a new derivation of the Murnaghan-Nakayama formula for irreducible symmetric group characters by summing diagonal matrix entries in Young's seminormal representations. We use the analogous representations of the Iwahori-Hecke algebra of $G(r,p,n)$ given by Ariki and Koike.

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