fof(ax_I2,axiom,(![A,B,L1,L2]:((point(A)&point(B)&line(L1)&line(L2)&A!=B&inc_po_l(A,L1)&inc_po_l(B,L1)&inc_po_l(A,L2)&inc_po_l(B,L2))=>(L1=L2)))).
