salam doste aziz shoma mitunid baranamtuno az in link daryaft konid
http://www.b4c4.com/functions/code.aspx?lid=14&fid=67
DelAll(x,L,L) :- Not-Member(x,L)
DelAll(x,[x|y],z) :- DelAll(x,y,z)
DelAll(x,[y|z],[y|k]) :- x≠y , DelAll(x,z,k)
Not-Member(x,L) :- Member(x,L) , ! , false
Not-Member(x,L)
Member(x,[y|z]) :- x≠y , Member(x,z)
Member(x,[x|y])