fact: Definition pred_of_vspace (U : space vT) : {pred vT} := fun v => (vs2mx (vline v) <= vs2mx U)%MS.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop finfun tuple) mathcomp(ssralg matrix mxalgebra zmodp)