Metamath Proof Explorer


Theorem latmlem2

Description: Add meet to both sides of a lattice ordering. ( sslin analog.) (Contributed by NM, 10-Nov-2011)

Ref Expression
Hypotheses latmle.b ⊢ B = Base K
latmle.l ⊢ ≤ ˙ = ≤ K
latmle.m ⊢ ∧ ˙ = meet ⁡ K
Assertion latmlem2 ⊢ K ∈ Lat ∧ X ∈ B ∧ Y ∈ B ∧ Z ∈ B → X ≤ ˙ Y → Z ∧ ˙ X ≤ ˙ Z ∧ ˙ Y

Proof

Step Hyp Ref Expression
1 latmle.b ⊢ B = Base K
2 latmle.l ⊢ ≤ ˙ = ≤ K
3 latmle.m ⊢ ∧ ˙ = meet ⁡ K
4 1 2 3 latmlem1 ⊢ K ∈ Lat ∧ X ∈ B ∧ Y ∈ B ∧ Z ∈ B → X ≤ ˙ Y → X ∧ ˙ Z ≤ ˙ Y ∧ ˙ Z
5 1 3 latmcom ⊢ K ∈ Lat ∧ X ∈ B ∧ Z ∈ B → X ∧ ˙ Z = Z ∧ ˙ X
6 5 3adant3r2 ⊢ K ∈ Lat ∧ X ∈ B ∧ Y ∈ B ∧ Z ∈ B → X ∧ ˙ Z = Z ∧ ˙ X
7 1 3 latmcom ⊢ K ∈ Lat ∧ Y ∈ B ∧ Z ∈ B → Y ∧ ˙ Z = Z ∧ ˙ Y
8 7 3adant3r1 ⊢ K ∈ Lat ∧ X ∈ B ∧ Y ∈ B ∧ Z ∈ B → Y ∧ ˙ Z = Z ∧ ˙ Y
9 6 8 breq12d ⊢ K ∈ Lat ∧ X ∈ B ∧ Y ∈ B ∧ Z ∈ B → X ∧ ˙ Z ≤ ˙ Y ∧ ˙ Z ↔ Z ∧ ˙ X ≤ ˙ Z ∧ ˙ Y
10 4 9 sylibd ⊢ K ∈ Lat ∧ X ∈ B ∧ Y ∈ B ∧ Z ∈ B → X ≤ ˙ Y → Z ∧ ˙ X ≤ ˙ Z ∧ ˙ Y