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Description: Under Disj , every block has a unique generator ( E* form). If t is a block in the quotient sense, then there is a uniquely determined u in dom R such that t = [ u ] R . This is the existence+uniqueness engine behind Disjs and QMap characterizations: it is the "representative theorem" from which the E! forms are obtained. (Contributed by Peter Mazsa, 5-Feb-2026)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | disjimrmoeqec | ⊢ ( Disj 𝑅 → ∃* 𝑢 ∈ dom 𝑅 𝑡 = [ 𝑢 ] 𝑅 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | disjimeceqim | ⊢ ( Disj 𝑅 → ∀ 𝑢 ∈ dom 𝑅 ∀ 𝑣 ∈ dom 𝑅 ( [ 𝑢 ] 𝑅 = [ 𝑣 ] 𝑅 → 𝑢 = 𝑣 ) ) | |
| 2 | eqtr2 | ⊢ ( ( 𝑡 = [ 𝑢 ] 𝑅 ∧ 𝑡 = [ 𝑣 ] 𝑅 ) → [ 𝑢 ] 𝑅 = [ 𝑣 ] 𝑅 ) | |
| 3 | 2 | imim1i | ⊢ ( ( [ 𝑢 ] 𝑅 = [ 𝑣 ] 𝑅 → 𝑢 = 𝑣 ) → ( ( 𝑡 = [ 𝑢 ] 𝑅 ∧ 𝑡 = [ 𝑣 ] 𝑅 ) → 𝑢 = 𝑣 ) ) |
| 4 | 3 | 2ralimi | ⊢ ( ∀ 𝑢 ∈ dom 𝑅 ∀ 𝑣 ∈ dom 𝑅 ( [ 𝑢 ] 𝑅 = [ 𝑣 ] 𝑅 → 𝑢 = 𝑣 ) → ∀ 𝑢 ∈ dom 𝑅 ∀ 𝑣 ∈ dom 𝑅 ( ( 𝑡 = [ 𝑢 ] 𝑅 ∧ 𝑡 = [ 𝑣 ] 𝑅 ) → 𝑢 = 𝑣 ) ) |
| 5 | 1 4 | syl | ⊢ ( Disj 𝑅 → ∀ 𝑢 ∈ dom 𝑅 ∀ 𝑣 ∈ dom 𝑅 ( ( 𝑡 = [ 𝑢 ] 𝑅 ∧ 𝑡 = [ 𝑣 ] 𝑅 ) → 𝑢 = 𝑣 ) ) |
| 6 | eceq1 | ⊢ ( 𝑢 = 𝑣 → [ 𝑢 ] 𝑅 = [ 𝑣 ] 𝑅 ) | |
| 7 | 6 | eqeq2d | ⊢ ( 𝑢 = 𝑣 → ( 𝑡 = [ 𝑢 ] 𝑅 ↔ 𝑡 = [ 𝑣 ] 𝑅 ) ) |
| 8 | 7 | rmo4 | ⊢ ( ∃* 𝑢 ∈ dom 𝑅 𝑡 = [ 𝑢 ] 𝑅 ↔ ∀ 𝑢 ∈ dom 𝑅 ∀ 𝑣 ∈ dom 𝑅 ( ( 𝑡 = [ 𝑢 ] 𝑅 ∧ 𝑡 = [ 𝑣 ] 𝑅 ) → 𝑢 = 𝑣 ) ) |
| 9 | 5 8 | sylibr | ⊢ ( Disj 𝑅 → ∃* 𝑢 ∈ dom 𝑅 𝑡 = [ 𝑢 ] 𝑅 ) |