Section Sound.
Context {L: Language}
{minL: MinimumLanguage L}
{pL: PropositionalLanguage L}
{MD: Model}
{SM: Semantics L MD}
{tminSM: TrivialMinimumSemantics L MD SM}
{tpSM: TrivialPropositionalSemantics L MD SM}.

Lemma sound_orp_elim:
forall x y z m,
m |= (x --> z) --> (y --> z) --> (x || y --> z).