%0 Journal Article
%A Leinders, Dirk
%A Jan Van Den Bussche
%T Repetitions and permutations of columns in the semijoin algebra
%J RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications
%D 2009
%P 179-187
%V 43
%N 2
%I EDP-Sciences
%U http://www.numdam.org/articles/10.1051/ita:2008023/
%R 10.1051/ita:2008023
%G en
%F ITA_2009__43_2_179_0