%0 Journal Article %A Nomura, Kazumasa %A Terwilliger, Paul %T Idempotent systems %J Algebraic Combinatorics %D 2021 %P 329-357 %V 4 %N 2 %I MathOA foundation %U https://alco.centre-mersenne.org/articles/10.5802/alco.159/ %R 10.5802/alco.159 %G en %F ALCO_2021__4_2_329_0