English
Let I,J be submodules; then le statements and dual relations extend to sums: I ≤ (J · J')ᵛ ↔ I · J ≤ J'ᵛ.
Русский
Пусть I,J,J' — подмодули; тогда отношение неравенства сохраняется для сумм: I ≤ (J·J')ᵛ ↔ I·J ≤ (J')ᵛ.
LaTeX
$$$I \le (J J')^{\\vee} \iff I J \le (J')^{\\vee}.$$$
Lean4
theorem one_le_traceDual_one : (1 : Submodule B L) ≤ 1ᵛ :=
by
rw [le_traceDual_iff_map_le_one, mul_one, one_eq_range]
rintro _ ⟨x, ⟨x, rfl⟩, rfl⟩
rw [mem_one]
apply IsIntegrallyClosed.isIntegral_iff.mp
apply isIntegral_trace
rw [IsIntegralClosure.isIntegral_iff (A := B)]
exact ⟨_, rfl⟩