Description: Define the fifth Gödel operation. This function takes two arguments and returns the intersection of the first argument with the domain of the second argument (see df-in and df-dm ). Based on the fifth case of Definition 14.2 of TakeutiZaring p. 144. (Contributed by BTernaryTau, 2-Sep-2026)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | df-gdlop5 | |- ~F5 = ( x e. _V , y e. _V |-> ( x i^i dom y ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 0 | cgdlop5 | |- ~F5 |
|
| 1 | vx | |- x |
|
| 2 | cvv | |- _V |
|
| 3 | vy | |- y |
|
| 4 | 1 | cv | |- x |
| 5 | 3 | cv | |- y |
| 6 | 5 | cdm | |- dom y |
| 7 | 4 6 | cin | |- ( x i^i dom y ) |
| 8 | 1 3 2 2 7 | cmpo | |- ( x e. _V , y e. _V |-> ( x i^i dom y ) ) |
| 9 | 0 8 | wceq | |- ~F5 = ( x e. _V , y e. _V |-> ( x i^i dom y ) ) |