English
The product of identity partial functions is the identity on the product type: (id α) × (id β) = id (Prod α β).
Русский
Произведение идентичности частичных функций равно идентичности на произведении: id α × id β = id (Prod α β).
LaTeX
$$$$ (\\mathrm{id}\\,\\alpha) \\prodMap (\\mathrm{id}\\,\\beta) = \\mathrm{id}\\, (\\mathrm{Prod}\\, \\alpha\\, \\beta). $$$$
Lean4
@[simp]
theorem prodMap_id_id : (PFun.id α).prodMap (PFun.id β) = PFun.id _ := by aesop