IsSubsetBlist( blist1, blist2 )
IsSubsetBlist returns true if  the boolean list  blist2 is a subset
of  the boolean list list1, which  must have equal  length, and false
otherwise.   blist2 is  a    subset if  blist1  if blist1[i]   =
blist1[i] or blist2[i] for all i.
    gap> blist1 := [ true, true, false, false ];;
    gap> blist2 := [ true, false, true, false ];;
    gap> IsSubsetBlist( blist1, blist2 );
    false
    gap> blist2 := [ true, false, false, false ];;
    gap> IsSubsetBlist( blist1, blist2 );
    true 
GAP 3.4.4