English
EqvGen Red.Step between L1 and L2 is equivalent to Join Red L1 L2.
Русский
EqvGen Red.Step между L1 и L2 эквивалентна Join Red L1 L2.
LaTeX
$$$EqvGen\;Red.Step\;L_1\;L_2 \iff Join\;Red\;L_1\;L_2$$$
Lean4
@[to_additive]
theorem eqvGen_step_iff_join_red : EqvGen Red.Step L₁ L₂ ↔ Join Red L₁ L₂ :=
Iff.intro
(fun h =>
have : EqvGen (Join Red) L₁ L₂ := h.mono fun _ _ => join_red_of_step
equivalence_join_red.eqvGen_iff.1 this)
(join_of_equivalence (Relation.EqvGen.is_equivalence _) fun _ _ =>
reflTransGen_of_equivalence (Relation.EqvGen.is_equivalence _) EqvGen.rel)