SKI
Reference : [Raymond] Mock a mocking Bird
# Definition
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S x y z := x z (y z)
K x y := x
I x := x
~~~
## I combinator
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S K x y = K y (y x) = y
S K K x = x
S K S x = x
I = ∀X. S K X
~~~
# Various Combinators (Birds)
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M x = x x # Mocking Bird
B x y z = x ( y z ) # Blue Bird
T x y = y x
~~~
(to be countinued ...)