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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 -> E* u e. dom R t = [ u ] R ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | disjimeceqim | |- ( Disj R -> A. u e. dom R A. v e. 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 | |- ( A. u e. dom R A. v e. dom R ( [ u ] R = [ v ] R -> u = v ) -> A. u e. dom R A. v e. dom R ( ( t = [ u ] R /\ t = [ v ] R ) -> u = v ) ) |
| 5 | 1 4 | syl | |- ( Disj R -> A. u e. dom R A. v e. 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 | |- ( E* u e. dom R t = [ u ] R <-> A. u e. dom R A. v e. dom R ( ( t = [ u ] R /\ t = [ v ] R ) -> u = v ) ) |
| 9 | 5 8 | sylibr | |- ( Disj R -> E* u e. dom R t = [ u ] R ) |