AsSpace( U )
returns the subspace U as a parent space.
gap> v:= GF(2)^2; v.name:="v";;
RowSpace( GF(2), [ [ Z(2)^0, 0*Z(2) ], [ 0*Z(2), Z(2)^0 ] ] )
gap> u:= Subspace( v, [ [ 1, 1 ] * Z(2) ] );
Subspace( v, [ [ Z(2)^0, Z(2)^0 ] ] )
gap> w:= AsSpace( u );
RowSpace( GF(2), [ [ Z(2)^0, Z(2)^0 ] ] )
gap> w = u;
true
GAP 3.4.4