assume [P1,P2,A] : (plane(P1) & plane(P2) & point(A) & P1!=P2 & inc_po_pl(A,P1) & inc_po_pl(A,P2))
let [B] : (point(B) & A!=B & inc_po_pl(B,P1) & inc_po_pl(B,P2))
let [L] : (line(L) & inc_po_l(A,L) & inc_po_l(B,L))
have (inc_l_pl(L,P1) & inc_l_pl(L,P2))
