-- -*- M2-comint -*- {* hash: -600029590 *}

i1 : P = intersection(matrix{{1,0},{0,1},{-1,-1}},matrix{{-1},{1},{-1}})

o1 = {ambient dimension => 2           }
      dimension of lineality space => 0
      dimension of polyhedron => -1
      number of facets => 0
      number of rays => 0
      number of vertices => 0

o1 : Polyhedron

i2 : isEmpty P

o2 = true

i3 :