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Description: Law of well-founded recursion over a partial order, part three. Finally, we show that F is unique. We do this by showing that any function H with the same properties we proved of F in fpr1 and fpr2 is identical to F . (Contributed by Scott Fenton, 11-Sep-2023)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | fprr.1 | |- F = frecs ( R , A , G ) |
|
| Assertion | fpr3 | |- ( ( ( R Fr A /\ R Po A /\ R Se A ) /\ ( H Fn A /\ A. z e. A ( H ` z ) = ( z G ( H |` Pred ( R , A , z ) ) ) ) ) -> F = H ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | fprr.1 | |- F = frecs ( R , A , G ) |
|
| 2 | simpl | |- ( ( ( R Fr A /\ R Po A /\ R Se A ) /\ ( H Fn A /\ A. z e. A ( H ` z ) = ( z G ( H |` Pred ( R , A , z ) ) ) ) ) -> ( R Fr A /\ R Po A /\ R Se A ) ) |
|
| 3 | 1 | fpr1 | |- ( ( R Fr A /\ R Po A /\ R Se A ) -> F Fn A ) |
| 4 | 1 | fpr2 | |- ( ( ( R Fr A /\ R Po A /\ R Se A ) /\ z e. A ) -> ( F ` z ) = ( z G ( F |` Pred ( R , A , z ) ) ) ) |
| 5 | 4 | ralrimiva | |- ( ( R Fr A /\ R Po A /\ R Se A ) -> A. z e. A ( F ` z ) = ( z G ( F |` Pred ( R , A , z ) ) ) ) |
| 6 | 3 5 | jca | |- ( ( R Fr A /\ R Po A /\ R Se A ) -> ( F Fn A /\ A. z e. A ( F ` z ) = ( z G ( F |` Pred ( R , A , z ) ) ) ) ) |
| 7 | 6 | adantr | |- ( ( ( R Fr A /\ R Po A /\ R Se A ) /\ ( H Fn A /\ A. z e. A ( H ` z ) = ( z G ( H |` Pred ( R , A , z ) ) ) ) ) -> ( F Fn A /\ A. z e. A ( F ` z ) = ( z G ( F |` Pred ( R , A , z ) ) ) ) ) |
| 8 | simpr | |- ( ( ( R Fr A /\ R Po A /\ R Se A ) /\ ( H Fn A /\ A. z e. A ( H ` z ) = ( z G ( H |` Pred ( R , A , z ) ) ) ) ) -> ( H Fn A /\ A. z e. A ( H ` z ) = ( z G ( H |` Pred ( R , A , z ) ) ) ) ) |
|
| 9 | fpr3g | |- ( ( ( R Fr A /\ R Po A /\ R Se A ) /\ ( F Fn A /\ A. z e. A ( F ` z ) = ( z G ( F |` Pred ( R , A , z ) ) ) ) /\ ( H Fn A /\ A. z e. A ( H ` z ) = ( z G ( H |` Pred ( R , A , z ) ) ) ) ) -> F = H ) |
|
| 10 | 2 7 8 9 | syl3anc | |- ( ( ( R Fr A /\ R Po A /\ R Se A ) /\ ( H Fn A /\ A. z e. A ( H ` z ) = ( z G ( H |` Pred ( R , A , z ) ) ) ) ) -> F = H ) |