English
If a morphism g : X → WidePullback satisfies g ≫ π_j = fs_j for all j and g ≫ base arrows = f, then g is the lift of f with fs and w; i.e., g = lift f fs w.
Русский
Если морфизм g : X → WidePullback удовлетворяет g ≫ π_j = fs_j для всех j и g ≫ base arrows = f, то g есть подъём lift f fs w.
LaTeX
$$$\\big(\\forall j:\\, J,\\; g \\circ \\pi arrows j = fs j\\big) \\land (g \\circ \\text{base arrows} = f) \\Rightarrow g = \\mathrm{lift}(f,fs,w).$$$
Lean4
theorem eq_lift_of_comp_eq (g : X ⟶ widePullback _ _ arrows) :
(∀ j : J, g ≫ π arrows j = fs j) → g ≫ base arrows = f → g = lift f fs w :=
by
intro h1 h2
apply (limit.isLimit (WidePullbackShape.wideCospan B objs arrows)).uniq (WidePullbackShape.mkCone f fs <| w)
rintro (_ | _)
· apply h2
· apply h1