Description: A function mapping Pell discriminants to the corresponding fundamental solution. (Contributed by Stefan O'Rear, 18-Sep-2014) (Revised by AV, 17-Sep-2020)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-pellfund | |- PellFund = ( x e. ( NN \ []NN ) |-> inf ( { z e. ( Pell14QR ` x ) | 1 < z } , RR , < ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 0 | cpellfund | |- PellFund | |
| 1 | vx | |- x | |
| 2 | cn | |- NN | |
| 3 | csquarenn | |- []NN | |
| 4 | 2 3 | cdif | |- ( NN \ []NN ) | 
| 5 | vz | |- z | |
| 6 | cpell14qr | |- Pell14QR | |
| 7 | 1 | cv | |- x | 
| 8 | 7 6 | cfv | |- ( Pell14QR ` x ) | 
| 9 | c1 | |- 1 | |
| 10 | clt | |- < | |
| 11 | 5 | cv | |- z | 
| 12 | 9 11 10 | wbr | |- 1 < z | 
| 13 | 12 5 8 | crab |  |-  { z e. ( Pell14QR ` x ) | 1 < z } | 
| 14 | cr | |- RR | |
| 15 | 13 14 10 | cinf |  |-  inf ( { z e. ( Pell14QR ` x ) | 1 < z } , RR , < ) | 
| 16 | 1 4 15 | cmpt |  |-  ( x e. ( NN \ []NN ) |-> inf ( { z e. ( Pell14QR ` x ) | 1 < z } , RR , < ) ) | 
| 17 | 0 16 | wceq |  |-  PellFund = ( x e. ( NN \ []NN ) |-> inf ( { z e. ( Pell14QR ` x ) | 1 < z } , RR , < ) ) |