Lattice Definition A lattice(structure )is a poset< A, <> in which any two elements a, b have a Lub(a, b) and a glb(a, b) From now on, we define aUb= LU B(a, b)and anb=glB(a, b)in brief. We also call them join and meet respectivelyLattice Definition A lattice (structure) is a poset < A, ≤> in which any two elements a, b have a LUB(a, b) and a GLB(a, b). From now on, we define a ∪ b = LUB(a, b) and a ∩ b = GLB(a, b) in brief. We also call them join and meet respectively. Yi Li (Fudan University) Discrete Mathematics February 28, 2012 8 / 15