English
There is an induction principle for PushoutI φ allowing to prove a property by checking generators and the base and closure under multiplication.
Русский
Для PushoutI φ существует принцип индукции: свойство доказывается по генераторам, по базе и сохраняется при произведении.
LaTeX
$$$\text{induction_on}: (\text{motive}) \; PushoutI(\varphi) → Prop$ with generator, base, and multiplication cases$$
Lean4
@[simp]
theorem ofCoprodI_of (i : ι) (g : G i) : (ofCoprodI (CoprodI.of g) : PushoutI φ) = of i g := by simp [ofCoprodI]