Metamath Proof Explorer


Theorem islvol4

Description: The predicate "is a 3-dim lattice volume". (Contributed by NM, 1-Jul-2012)

Ref Expression
Hypotheses lvolset.b ⊢ B = Base K
lvolset.c ⊢ C = ⋖ K
lvolset.p ⊢ P = LPlanes ⁡ K
lvolset.v ⊢ V = LVols ⁡ K
Assertion islvol4 ⊢ K ∈ A ∧ X ∈ B → X ∈ V ↔ ∃ y ∈ P y C X

Proof

Step Hyp Ref Expression
1 lvolset.b ⊢ B = Base K
2 lvolset.c ⊢ C = ⋖ K
3 lvolset.p ⊢ P = LPlanes ⁡ K
4 lvolset.v ⊢ V = LVols ⁡ K
5 1 2 3 4 islvol ⊢ K ∈ A → X ∈ V ↔ X ∈ B ∧ ∃ y ∈ P y C X
6 5 baibd ⊢ K ∈ A ∧ X ∈ B → X ∈ V ↔ ∃ y ∈ P y C X