Metamath Proof Explorer < Previous   Next > Nearby theorems Mirrors  >  Home  >  MPE Home  >  Th. List  >  joincomALT Structured version   Visualization version   GIF version

Theorem joincomALT 17718
 Description: The join of a poset commutes. (This may not be a theorem under other definitions of meet.) (Contributed by NM, 16-Sep-2011.) (New usage is discouraged.) (Proof modification is discouraged.)
Hypotheses
Ref Expression
joincom.b 𝐵 = (Base‘𝐾)
joincom.j = (join‘𝐾)
Assertion
Ref Expression
joincomALT ((𝐾𝑉𝑋𝐵𝑌𝐵) → (𝑋 𝑌) = (𝑌 𝑋))

Proof of Theorem joincomALT
StepHypRef Expression
1 prcom 4628 . . . 4 {𝑌, 𝑋} = {𝑋, 𝑌}
21fveq2i 6666 . . 3 ((lub‘𝐾)‘{𝑌, 𝑋}) = ((lub‘𝐾)‘{𝑋, 𝑌})
32a1i 11 . 2 ((𝐾𝑉𝑋𝐵𝑌𝐵) → ((lub‘𝐾)‘{𝑌, 𝑋}) = ((lub‘𝐾)‘{𝑋, 𝑌}))
4 eqid 2758 . . 3 (lub‘𝐾) = (lub‘𝐾)
5 joincom.j . . 3 = (join‘𝐾)
6 simp1 1133 . . 3 ((𝐾𝑉𝑋𝐵𝑌𝐵) → 𝐾𝑉)
7 simp3 1135 . . 3 ((𝐾𝑉𝑋𝐵𝑌𝐵) → 𝑌𝐵)
8 simp2 1134 . . 3 ((𝐾𝑉𝑋𝐵𝑌𝐵) → 𝑋𝐵)
94, 5, 6, 7, 8joinval 17694 . 2 ((𝐾𝑉𝑋𝐵𝑌𝐵) → (𝑌 𝑋) = ((lub‘𝐾)‘{𝑌, 𝑋}))
104, 5, 6, 8, 7joinval 17694 . 2 ((𝐾𝑉𝑋𝐵𝑌𝐵) → (𝑋 𝑌) = ((lub‘𝐾)‘{𝑋, 𝑌}))
113, 9, 103eqtr4rd 2804 1 ((𝐾𝑉𝑋𝐵𝑌𝐵) → (𝑋 𝑌) = (𝑌 𝑋))
 Colors of variables: wff setvar class Syntax hints:   → wi 4   ∧ w3a 1084   = wceq 1538   ∈ wcel 2111  {cpr 4527  ‘cfv 6340  (class class class)co 7156  Basecbs 16554  lubclub 17631  joincjn 17633 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1911  ax-6 1970  ax-7 2015  ax-8 2113  ax-9 2121  ax-10 2142  ax-11 2158  ax-12 2175  ax-ext 2729  ax-rep 5160  ax-sep 5173  ax-nul 5180  ax-pow 5238  ax-pr 5302  ax-un 7465 This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-3an 1086  df-tru 1541  df-fal 1551  df-ex 1782  df-nf 1786  df-sb 2070  df-mo 2557  df-eu 2588  df-clab 2736  df-cleq 2750  df-clel 2830  df-nfc 2901  df-ne 2952  df-ral 3075  df-rex 3076  df-reu 3077  df-rab 3079  df-v 3411  df-sbc 3699  df-csb 3808  df-dif 3863  df-un 3865  df-in 3867  df-ss 3877  df-nul 4228  df-if 4424  df-pw 4499  df-sn 4526  df-pr 4528  df-op 4532  df-uni 4802  df-iun 4888  df-br 5037  df-opab 5099  df-mpt 5117  df-id 5434  df-xp 5534  df-rel 5535  df-cnv 5536  df-co 5537  df-dm 5538  df-rn 5539  df-res 5540  df-ima 5541  df-iota 6299  df-fun 6342  df-fn 6343  df-f 6344  df-f1 6345  df-fo 6346  df-f1o 6347  df-fv 6348  df-riota 7114  df-ov 7159  df-oprab 7160  df-lub 17663  df-join 17665 This theorem is referenced by:  joincom  17719
 Copyright terms: Public domain W3C validator