Description: Define the class of all fixpoints of a relationship. (Contributed by Scott Fenton, 11-Apr-2012)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-fix | ⊢ Fix 𝐴 = dom ( 𝐴 ∩ I ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | cA | ⊢ 𝐴 | |
| 1 | 0 | cfix | ⊢ Fix 𝐴 |
| 2 | cid | ⊢ I | |
| 3 | 0 2 | cin | ⊢ ( 𝐴 ∩ I ) |
| 4 | 3 | cdm | ⊢ dom ( 𝐴 ∩ I ) |
| 5 | 1 4 | wceq | ⊢ Fix 𝐴 = dom ( 𝐴 ∩ I ) |