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Description: Part of proof of Lemma E in Crawley p. 113, 5th paragraph on p. 114, 1st line. D represents s_2. In their notation, we prove that if r <_ s \/ t, then s_2=(s \/ t) /\ w. (Contributed by NM, 13-Nov-2012)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | cdleme19.l | ⊢ ≤ = ( le ‘ 𝐾 ) | |
| cdleme19.j | ⊢ ∨ = ( join ‘ 𝐾 ) | ||
| cdleme19.m | ⊢ ∧ = ( meet ‘ 𝐾 ) | ||
| cdleme19.a | ⊢ 𝐴 = ( Atoms ‘ 𝐾 ) | ||
| cdleme19.h | ⊢ 𝐻 = ( LHyp ‘ 𝐾 ) | ||
| cdleme19.u | ⊢ 𝑈 = ( ( 𝑃 ∨ 𝑄 ) ∧ 𝑊 ) | ||
| cdleme19.f | ⊢ 𝐹 = ( ( 𝑆 ∨ 𝑈 ) ∧ ( 𝑄 ∨ ( ( 𝑃 ∨ 𝑆 ) ∧ 𝑊 ) ) ) | ||
| cdleme19.g | ⊢ 𝐺 = ( ( 𝑇 ∨ 𝑈 ) ∧ ( 𝑄 ∨ ( ( 𝑃 ∨ 𝑇 ) ∧ 𝑊 ) ) ) | ||
| cdleme19.d | ⊢ 𝐷 = ( ( 𝑅 ∨ 𝑆 ) ∧ 𝑊 ) | ||
| cdleme19.y | ⊢ 𝑌 = ( ( 𝑅 ∨ 𝑇 ) ∧ 𝑊 ) | ||
| Assertion | cdleme19a | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝐷 = ( ( 𝑆 ∨ 𝑇 ) ∧ 𝑊 ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | cdleme19.l | ⊢ ≤ = ( le ‘ 𝐾 ) | |
| 2 | cdleme19.j | ⊢ ∨ = ( join ‘ 𝐾 ) | |
| 3 | cdleme19.m | ⊢ ∧ = ( meet ‘ 𝐾 ) | |
| 4 | cdleme19.a | ⊢ 𝐴 = ( Atoms ‘ 𝐾 ) | |
| 5 | cdleme19.h | ⊢ 𝐻 = ( LHyp ‘ 𝐾 ) | |
| 6 | cdleme19.u | ⊢ 𝑈 = ( ( 𝑃 ∨ 𝑄 ) ∧ 𝑊 ) | |
| 7 | cdleme19.f | ⊢ 𝐹 = ( ( 𝑆 ∨ 𝑈 ) ∧ ( 𝑄 ∨ ( ( 𝑃 ∨ 𝑆 ) ∧ 𝑊 ) ) ) | |
| 8 | cdleme19.g | ⊢ 𝐺 = ( ( 𝑇 ∨ 𝑈 ) ∧ ( 𝑄 ∨ ( ( 𝑃 ∨ 𝑇 ) ∧ 𝑊 ) ) ) | |
| 9 | cdleme19.d | ⊢ 𝐷 = ( ( 𝑅 ∨ 𝑆 ) ∧ 𝑊 ) | |
| 10 | cdleme19.y | ⊢ 𝑌 = ( ( 𝑅 ∨ 𝑇 ) ∧ 𝑊 ) | |
| 11 | eqid | ⊢ ( Base ‘ 𝐾 ) = ( Base ‘ 𝐾 ) | |
| 12 | hllat | ⊢ ( 𝐾 ∈ HL → 𝐾 ∈ Lat ) | |
| 13 | 12 | 3ad2ant1 | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝐾 ∈ Lat ) |
| 14 | simp1 | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝐾 ∈ HL ) | |
| 15 | simp21 | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝑅 ∈ 𝐴 ) | |
| 16 | simp22 | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝑆 ∈ 𝐴 ) | |
| 17 | 11 2 4 | hlatjcl | ⊢ ( ( 𝐾 ∈ HL ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ) → ( 𝑅 ∨ 𝑆 ) ∈ ( Base ‘ 𝐾 ) ) |
| 18 | 14 15 16 17 | syl3anc | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → ( 𝑅 ∨ 𝑆 ) ∈ ( Base ‘ 𝐾 ) ) |
| 19 | simp23 | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝑇 ∈ 𝐴 ) | |
| 20 | 11 2 4 | hlatjcl | ⊢ ( ( 𝐾 ∈ HL ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) → ( 𝑆 ∨ 𝑇 ) ∈ ( Base ‘ 𝐾 ) ) |
| 21 | 14 16 19 20 | syl3anc | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → ( 𝑆 ∨ 𝑇 ) ∈ ( Base ‘ 𝐾 ) ) |
| 22 | simp33 | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) | |
| 23 | 1 2 4 | hlatlej1 | ⊢ ( ( 𝐾 ∈ HL ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) → 𝑆 ≤ ( 𝑆 ∨ 𝑇 ) ) |
| 24 | 14 16 19 23 | syl3anc | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝑆 ≤ ( 𝑆 ∨ 𝑇 ) ) |
| 25 | 11 4 | atbase | ⊢ ( 𝑅 ∈ 𝐴 → 𝑅 ∈ ( Base ‘ 𝐾 ) ) |
| 26 | 15 25 | syl | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝑅 ∈ ( Base ‘ 𝐾 ) ) |
| 27 | 11 4 | atbase | ⊢ ( 𝑆 ∈ 𝐴 → 𝑆 ∈ ( Base ‘ 𝐾 ) ) |
| 28 | 16 27 | syl | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝑆 ∈ ( Base ‘ 𝐾 ) ) |
| 29 | 11 1 2 | latjle12 | ⊢ ( ( 𝐾 ∈ Lat ∧ ( 𝑅 ∈ ( Base ‘ 𝐾 ) ∧ 𝑆 ∈ ( Base ‘ 𝐾 ) ∧ ( 𝑆 ∨ 𝑇 ) ∈ ( Base ‘ 𝐾 ) ) ) → ( ( 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ∧ 𝑆 ≤ ( 𝑆 ∨ 𝑇 ) ) ↔ ( 𝑅 ∨ 𝑆 ) ≤ ( 𝑆 ∨ 𝑇 ) ) ) |
| 30 | 13 26 28 21 29 | syl13anc | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → ( ( 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ∧ 𝑆 ≤ ( 𝑆 ∨ 𝑇 ) ) ↔ ( 𝑅 ∨ 𝑆 ) ≤ ( 𝑆 ∨ 𝑇 ) ) ) |
| 31 | 22 24 30 | mpbi2and | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → ( 𝑅 ∨ 𝑆 ) ≤ ( 𝑆 ∨ 𝑇 ) ) |
| 32 | 1 2 4 | hlatlej2 | ⊢ ( ( 𝐾 ∈ HL ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ) → 𝑆 ≤ ( 𝑅 ∨ 𝑆 ) ) |
| 33 | 14 15 16 32 | syl3anc | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝑆 ≤ ( 𝑅 ∨ 𝑆 ) ) |
| 34 | hlcvl | ⊢ ( 𝐾 ∈ HL → 𝐾 ∈ CvLat ) | |
| 35 | 34 | 3ad2ant1 | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝐾 ∈ CvLat ) |
| 36 | simp31 | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ) | |
| 37 | simp32 | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ) | |
| 38 | nbrne2 | ⊢ ( ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ) → 𝑅 ≠ 𝑆 ) | |
| 39 | 36 37 38 | syl2anc | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝑅 ≠ 𝑆 ) |
| 40 | 1 2 4 | cvlatexch1 | ⊢ ( ( 𝐾 ∈ CvLat ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ) ∧ 𝑅 ≠ 𝑆 ) → ( 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) → 𝑇 ≤ ( 𝑆 ∨ 𝑅 ) ) ) |
| 41 | 35 15 19 16 39 40 | syl131anc | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → ( 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) → 𝑇 ≤ ( 𝑆 ∨ 𝑅 ) ) ) |
| 42 | 22 41 | mpd | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝑇 ≤ ( 𝑆 ∨ 𝑅 ) ) |
| 43 | 2 4 | hlatjcom | ⊢ ( ( 𝐾 ∈ HL ∧ 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ) → ( 𝑅 ∨ 𝑆 ) = ( 𝑆 ∨ 𝑅 ) ) |
| 44 | 14 15 16 43 | syl3anc | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → ( 𝑅 ∨ 𝑆 ) = ( 𝑆 ∨ 𝑅 ) ) |
| 45 | 42 44 | breqtrrd | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝑇 ≤ ( 𝑅 ∨ 𝑆 ) ) |
| 46 | 11 4 | atbase | ⊢ ( 𝑇 ∈ 𝐴 → 𝑇 ∈ ( Base ‘ 𝐾 ) ) |
| 47 | 19 46 | syl | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝑇 ∈ ( Base ‘ 𝐾 ) ) |
| 48 | 11 1 2 | latjle12 | ⊢ ( ( 𝐾 ∈ Lat ∧ ( 𝑆 ∈ ( Base ‘ 𝐾 ) ∧ 𝑇 ∈ ( Base ‘ 𝐾 ) ∧ ( 𝑅 ∨ 𝑆 ) ∈ ( Base ‘ 𝐾 ) ) ) → ( ( 𝑆 ≤ ( 𝑅 ∨ 𝑆 ) ∧ 𝑇 ≤ ( 𝑅 ∨ 𝑆 ) ) ↔ ( 𝑆 ∨ 𝑇 ) ≤ ( 𝑅 ∨ 𝑆 ) ) ) |
| 49 | 13 28 47 18 48 | syl13anc | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → ( ( 𝑆 ≤ ( 𝑅 ∨ 𝑆 ) ∧ 𝑇 ≤ ( 𝑅 ∨ 𝑆 ) ) ↔ ( 𝑆 ∨ 𝑇 ) ≤ ( 𝑅 ∨ 𝑆 ) ) ) |
| 50 | 33 45 49 | mpbi2and | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → ( 𝑆 ∨ 𝑇 ) ≤ ( 𝑅 ∨ 𝑆 ) ) |
| 51 | 11 1 13 18 21 31 50 | latasymd | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → ( 𝑅 ∨ 𝑆 ) = ( 𝑆 ∨ 𝑇 ) ) |
| 52 | 51 | oveq1d | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → ( ( 𝑅 ∨ 𝑆 ) ∧ 𝑊 ) = ( ( 𝑆 ∨ 𝑇 ) ∧ 𝑊 ) ) |
| 53 | 9 52 | eqtrid | ⊢ ( ( 𝐾 ∈ HL ∧ ( 𝑅 ∈ 𝐴 ∧ 𝑆 ∈ 𝐴 ∧ 𝑇 ∈ 𝐴 ) ∧ ( 𝑅 ≤ ( 𝑃 ∨ 𝑄 ) ∧ ¬ 𝑆 ≤ ( 𝑃 ∨ 𝑄 ) ∧ 𝑅 ≤ ( 𝑆 ∨ 𝑇 ) ) ) → 𝐷 = ( ( 𝑆 ∨ 𝑇 ) ∧ 𝑊 ) ) |