Hint Resolve perp_symmetry perp_commutativity perp_left_commutativity perp_right_commutativity : sPerp.
Hint Resolve perp_in_symmetry perp_in_commutativity perp_in_left_commutativity perp_in_right_commutativity : sPerp.
Ltac sPerp := eauto with sPerp.

Lemma perp_col : forall A B C D E,
A<>E ->
Perp A B C D -> Col A B E -> Perp A E C D.