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A comment on Fixed-Point Combinator. Parent comment

Re:Fixed-Point Combinator by svat on Friday February 23, 2024 @09:13PM (#39488509)
What do you mean by "the opposite"? In your notation, the example shows that

    Y(g) = g(Y(g))
which by the definition of the equals sign (A=B and B=A say the same thing), is the same as:

    g(Y(g)) = Y(g)
— so Y(g) is a fixed point of g. What is the confusion?
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Re:Fixed-Point Combinator by konstantinua00 on Tuesday February 27, 2024 @10:10PM (#39533488)
confusion in that if you treat lambda calculus as computation instead of "mathematical truths", then following the proof in the opposite direction requires conjuring out of thin air a complicated construction that isn't obvious from the state you'd have
[ Parent | on HN ]