Require Export B12_Tacticques_base.
Section HALFLINE_PROPERTIES.

(* Specifications: *)
Lemma HalfLineNotClockwiseABC : forall A B C,
HalfLine A B C -> ~Clockwise A B C.
Lemma HalfLineNotClockwiseBAC : forall A B C,
HalfLine A B C -> ~Clockwise B A C.
Lemma HalfLineCollinear : forall A B C,
HalfLine A B C -> Collinear A B C.
Lemma HalfLineSym : forall A B C,
A <> B ->
HalfLine A B C ->
HalfLine A C B.
Lemma ClockwiseNotHalfLine : forall A B C,
Clockwise A B C ->
~HalfLine A B C.
Lemma HalfLineDistinct : forall A B C,
A <> B ->
HalfLine A B C ->
A <> C.