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## app3

Basis Function Combinator

Like app1 with three items.

:   ... z y x [Q] . app3
        -----------------------------------
        ... [z ...] [Q] . infra first
          [y ...] [Q]   infra first
          [x ...] [Q]   infra first

Gentzen diagram.

### Definition

if not basis.

### Derivation

if not basis.

### Source

if basis

### Discussion

Lorem ipsum.

### Crosslinks

Lorem ipsum.