subseteq l math join ie least upper bound denoted math vee b math called '''meet semilattice''' two element subset meet ie greatest lower bound denoted math wedge b math math l leq math called '''lattice''' join meet semilattice definition makes math wedge math math vee math binary operations operations monotone respect given order math leq math math b leq b math implies math vee b leq vee b math math wedge b leq wedge b math follows induction argument every
Formal science Mathematics Pure mathematics Algebra Lattice theory