English
If α is a lattice, then WithTop(α) forms a lattice with the induced operations.
Русский
Если α — решето (лат) (lattice), то WithTop(α) образует решето с индивидуальными операциями.
LaTeX
$$$$ \\text{WithTop}(\\alpha) \\text{ is a lattice for } [\\text{Lattice } \\alpha]. $$$$
Lean4
instance lattice [Lattice α] : Lattice (WithTop α) :=
{ WithTop.semilatticeSup, WithTop.semilatticeInf with }