On a method of determining supports of Thoma's characters of discrete groups
Annales Polonici Mathematici, Tome 67 (1997) no. 2, pp. 199-202
Cet article a éte moissonné depuis la source Institute of Mathematics Polish Academy of Sciences
We present a new approach to determining supports of extreme, normed by 1, positive definite class functions of discrete groups, i.e. characters in the sense of E. Thoma [8]. Any character of a group produces a unitary representation and thus a von Neumann algebra of linear operators with finite normal trace. We use a theorem of H. Umegaki [9] on the uniqueness of conditional expectation in finite von Neumann algebras. Some applications and examples are given.
Keywords:
positive definite functions, characters, traces
Affiliations des auteurs :
Ernest Płonka 1
@article{10_4064_ap_67_2_199_202,
author = {Ernest P{\l}onka},
title = {On a method of determining supports of {Thoma's} characters of discrete groups},
journal = {Annales Polonici Mathematici},
pages = {199--202},
year = {1997},
volume = {67},
number = {2},
doi = {10.4064/ap-67-2-199-202},
language = {en},
url = {http://geodesic.mathdoc.fr/articles/10.4064/ap-67-2-199-202/}
}
TY - JOUR AU - Ernest Płonka TI - On a method of determining supports of Thoma's characters of discrete groups JO - Annales Polonici Mathematici PY - 1997 SP - 199 EP - 202 VL - 67 IS - 2 UR - http://geodesic.mathdoc.fr/articles/10.4064/ap-67-2-199-202/ DO - 10.4064/ap-67-2-199-202 LA - en ID - 10_4064_ap_67_2_199_202 ER -
%0 Journal Article %A Ernest Płonka %T On a method of determining supports of Thoma's characters of discrete groups %J Annales Polonici Mathematici %D 1997 %P 199-202 %V 67 %N 2 %U http://geodesic.mathdoc.fr/articles/10.4064/ap-67-2-199-202/ %R 10.4064/ap-67-2-199-202 %G en %F 10_4064_ap_67_2_199_202
Ernest Płonka. On a method of determining supports of Thoma's characters of discrete groups. Annales Polonici Mathematici, Tome 67 (1997) no. 2, pp. 199-202. doi: 10.4064/ap-67-2-199-202
Cité par Sources :