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A comment on Tree Calculus. Parent comment

Re:Tree Calculus by tromp on Wednesday December 11, 2024 @04:48AM (#42386300)
> I = SK

Wrong. I = S K M where M can be anything:

    I x = S K M x = K x (M x) = x
K and S K represent True and False, since K x y = x and S K x y = y.

> essentially an obfuscated mix of S and K

Most alternatives are tuples of S and K like λz. z S K or λz. z K S K. But the arguably shortest one is indeed a proper mix:

    A = λx λy λz. x z (y (λ. z)) = λx λy λz. x z (y (K z))
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Re:Tree Calculus by chriswarbo on Wednesday December 11, 2024 @07:39AM (#42387148)
Oops, sorry; I got part way through writing I = S K K, but went off to another tab to double-check, and forgot to update that expression when I came back!

You're absolutely right.

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