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carlineng | 2 years ago

My favorite discussion of this topic is from David Beazley: https://www.youtube.com/watch?v=5C6sv7-eTKg

He does a wonderful job of taking very dense mathematical notation and explaining it in ways that anyone can understand. He derives the basic concepts of the lambda calculus from the ground up using Python. Super fun to follow along with.

discuss

order

photochemsyn|2 years ago

That looks interesting, although it is 3 hrs. I like this ~45 minute intro to the concept, which seems a little more Turing-accesible:, in that it shows how you can implement addition and multiplication in the system, which is a lot:

https://youtu.be/OLH3L285EiY

successor function: given a number, get the next number

try this in Python:

zero = lambda f: lambda x: x

one = lambda f: lambda x: f(x)

two = lambda f: lambda x: f(f(x))

to_int = lambda n: n(lambda i: i+1)(0)

succ = lambda n: lambda f: lambda x: f(n(f)(x))

three = succ(two)

four = succ(three)

to_int(four)

So that's just counting, the Church Numerals, where it begins.

cloudripper|2 years ago

Thanks for sharing. He makes the material very interesting and very accessible. I've fallen into another HN rabbithole..