Commit 2026-09-30 00:55 3f91e898
View on Github →chore(Order): move the definition of lattices to a new file (#44002)
This PR adds a file Mathlib/Order/Defs/Lattice.lean for the definitions and basic properties of Semilattice{Inf,Sup}, Lattice and DistribLattice. This file has minimal imports, in particular, it does not import LinearOrder, so this will make it possible to have LinearOrder extend Lattice in the future.
The proof in DistribLattice.ofInfSupLe (which is used by to_dual for dualizing DistribLattice.mk) had to be replaced with a manual proof because OrderDual is not imported in this file.