let R be Relation; :: thesis: ( R is being_partial-order implies R is being_quasi-order )
assume ( R is reflexive & R is transitive & R is antisymmetric ) ; :: according to ORDERS_1:def 4 :: thesis: R is being_quasi-order
hence ( R is reflexive & R is transitive ) ; :: according to ORDERS_1:def 3 :: thesis: verum