English
On an element x in the projecting submodule, g.toLinearPMap x equals valFromGraph hg x.2.
Русский
На элементе x из проекции графа g.toLinearPMap x равно valFromGraph hg x.2.
LaTeX
$$g.toLinearPMap x = valFromGraph hg x.2$$
Lean4
/-- Define a `LinearPMap` from its graph.
In the case that the submodule is not a graph of a `LinearPMap` then the underlying linear map
is just the zero map. -/
noncomputable def toLinearPMap (g : Submodule R (E × F)) : E →ₗ.[R] F
where
domain := g.map (LinearMap.fst R E F)
toFun := if hg : ∀ (x : E × F) (_hx : x ∈ g) (_hx' : x.fst = 0), x.snd = 0 then g.toLinearPMapAux hg else 0