English
If α and β are lattices, then α × β is a lattice with coordinatewise operations: (a,b) ⊔ (c,d) = (a ⊔ c, b ⊔ d) and (a,b) ⊓ (c,d) = (a ⊓ c, b ⊓ d).
Русский
Если α и β — решётки, то α×β — решётка, коэффициентно задаваемая через ⊔ и ⊓: (a,b) ⊔ (c,d) = (a ⊔ c, b ⊔ d), (a,b) ⊓ (c,d) = (a ⊓ c, b ⊓ d).
LaTeX
$$$ (a,b) \lor (c,d) = (a \lor c, b \lor d) \quad\land\quad (a,b) \land (c,d) = (a \land c, b \land d) $$$
Lean4
instance instLattice [Lattice α] [Lattice β] : Lattice (α × β) where