proposition: Theorem lt_lopt `{Funext} {L R : Type@{i}} {s : InSort S L R} (xL : L -> No) (xR : R -> No) (xcut : forall (l:L) (r:R), (xL l) < (xR r)) (l : L) : xL l < {{ xL | xR // xcut }}.
proof: Proof. refine (Conway_theorem0_lemma1 (xL l) _ _ _ _ _ 1). apply le_reflexive. Defined.
imports: HoTT.Basics HoTT.Types TruncType HSet HoTT.Truncations.Core