English
Similarly, for submodules U(i) of Module.Dual(R,M), the dual coannihilator of the supremum equals the infimum of the dual coannihilators: (⨆ i, U(i)).dualCoannihilator = ⨅ i, (U(i)).dualCoannihilator.
Русский
Аналогично: (⨆ i, U(i)).dualCoannihilator = ⨅ i, (U(i)).dualCoannihilator.
LaTeX
$$$ \\big(\\big\\vee_{i} U(i)\\big).dualCoannihilator = \\bigwedge_{i} (U(i)).dualCoannihilator $$$
Lean4
theorem dualCoannihilator_iSup_eq {ι : Sort*} (U : ι → Submodule R (Module.Dual R M)) :
(⨆ i : ι, U i).dualCoannihilator = ⨅ i : ι, (U i).dualCoannihilator :=
(dualAnnihilator_gc R M).u_iInf