%0 Journal Article %A Thiem, Nathaniel %T Supercharacter theories of type $A$ unipotent radicals and unipotent polytopes %J Algebraic Combinatorics %D 2018 %P 23-45 %V 1 %N 1 %I MathOA foundation %U http://archive.numdam.org/articles/10.5802/alco.3/ %R 10.5802/alco.3 %G en %F ALCO_2018__1_1_23_0