fact: Definition lfun_img_def aT rT f (U : {vspace aT}) : {vspace rT} := mx2vs (vs2mx U *m f2mx f).
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop finfun tuple) mathcomp(ssralg matrix mxalgebra zmodp)