English
For submodules U,V of Module.Dual(R,M), the join of their dual coannihilators equals the meet of their dual annihilators: (U ⊔ V).dualCoannihilator = U.dualCoannihilator ⊓ V.dualCoannihilator.
Русский
Для U,V ⊆ M в дуальном модуле выполняется: (U ⊔ V).dualCoannihilator = U.dualCoannihilator ⊓ V.dualCoannihilator.
LaTeX
$$$ (U \\or V).dualCoannihilator = U.dualCoannihilator \\cap V.dualCoannihilator $$$
Lean4
theorem dualCoannihilator_sup_eq (U V : Submodule R (Module.Dual R M)) :
(U ⊔ V).dualCoannihilator = U.dualCoannihilator ⊓ V.dualCoannihilator :=
(dualAnnihilator_gc R M).u_inf