English
Two compatible families on the sieve generated by R are equal if their restrictions to R are equal.
Русский
Две совместимые семьи на сгенерированном через R ситах равны, если их ограничения до R равны.
LaTeX
$$$x_1.Compatible \\to x_2.Compatible \\to (x_1.restrict( le\_generate(R) ) = x_2.restrict(le\_generate(R))) \Rightarrow x_1 = x_2$$$
Lean4
/-- Two compatible families on the sieve generated by a presieve `R` are equal if and only if they are
equal when restricted to `R`.
-/
theorem restrict_inj {x₁ x₂ : FamilyOfElements P (generate R).arrows} (t₁ : x₁.Compatible) (t₂ : x₂.Compatible) :
x₁.restrict (le_generate R) = x₂.restrict (le_generate R) → x₁ = x₂ := fun h =>
by
rw [← extend_restrict t₁, ← extend_restrict t₂]
congr