Description: Functionality of the projection function. (Contributed by NM, 24-Apr-2006) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | pjmfn | |- projh Fn CH |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ax-hilex | |- ~H e. _V |
|
| 2 | 1 | mptex | |- ( x e. ~H |-> ( iota_ z e. h E. y e. ( _|_ ` h ) x = ( z +h y ) ) ) e. _V |
| 3 | df-pjh | |- projh = ( h e. CH |-> ( x e. ~H |-> ( iota_ z e. h E. y e. ( _|_ ` h ) x = ( z +h y ) ) ) ) |
|
| 4 | 2 3 | fnmpti | |- projh Fn CH |