English
The graph of a partial function f is the set of pairs (x, y) with y ∈ f(x).
Русский
Граф частичной функции f — множество пар (x, y) таких, что y ∈ f(x).
LaTeX
$$$\\mathrm{graph}(f) = \\{ (x,y) \\mid y \\in f(x)\\}$$$
Lean4
/-- Graph of a partial function `f` as the set of pairs `(x, f x)` where `x` is in the domain of
`f`. -/
def graph (f : α →. β) : Set (α × β) :=
{p | p.2 ∈ f p.1}