English
PrincipalSeg toRelEmbedding is injective given IsIrrefl and IsTrichotomous on β; f and g have equal toRelEmbedding implies f = g.
Русский
toRelEmbedding для PrincipalSeg инъективно при IsIrrefl и IsTrichotomous на β; равенство toRelEmbedding двух элементов влечет равенство самих элементов.
LaTeX
$$$[IsIrrefl \\ β \\ s] [IsTrichotomous \\ β \\ s] : Function.Injective (toRelEmbedding).$$$
Lean4
theorem toRelEmbedding_injective [IsIrrefl β s] [IsTrichotomous β s] : Function.Injective (@toRelEmbedding α β r s) :=
by
rintro ⟨f, a, hf⟩ ⟨g, b, hg⟩ rfl
congr
refine extensional_of_trichotomous_of_irrefl s fun x ↦ ?_
rw [← hf, hg]