Description: Define the concept of a successor in a well-founded set. (Contributed by Scott Fenton, 13-Jun-2018) (Revised by AV, 10-Oct-2021)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-wsuc | ⊢ wsuc ( 𝑅 , 𝐴 , 𝑋 ) = inf ( Pred ( ◡ 𝑅 , 𝐴 , 𝑋 ) , 𝐴 , 𝑅 ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | cR | ⊢ 𝑅 | |
| 1 | cA | ⊢ 𝐴 | |
| 2 | cX | ⊢ 𝑋 | |
| 3 | 1 0 2 | cwsuc | ⊢ wsuc ( 𝑅 , 𝐴 , 𝑋 ) |
| 4 | 0 | ccnv | ⊢ ◡ 𝑅 |
| 5 | 1 4 2 | cpred | ⊢ Pred ( ◡ 𝑅 , 𝐴 , 𝑋 ) |
| 6 | 5 1 0 | cinf | ⊢ inf ( Pred ( ◡ 𝑅 , 𝐴 , 𝑋 ) , 𝐴 , 𝑅 ) |
| 7 | 3 6 | wceq | ⊢ wsuc ( 𝑅 , 𝐴 , 𝑋 ) = inf ( Pred ( ◡ 𝑅 , 𝐴 , 𝑋 ) , 𝐴 , 𝑅 ) |