Lambda Calculus - Fundamentals of Lambda Calculus & Functional Programming in JavaScript

The Lambda Calculus is a symbol manipulation system which suffices to calculate anything calculable. This branch of pure mathematics forms the backbone of functional programming languages, and here it is presented through the concrete and familiar lens of JavaScript.

In this Lambda Calculus video you will learn:

- Lambda Calculus Syntax
- History of the foundations of mathematical logic
- The essence of functional programming

[tashburn]

This was the clearest, most understandable introduction to lambda calculus I'm come across. Nicely done. Thanks for making it.

[alinisar]

This is hands down the best intro to functional programming/lambda calculus out there. The fact that it only has 38k views at the time of writing is a crime of untold magnitude.

[ninichanglife]

the best lambda calculus explanation ever

[itskshitij]

Just want to say, those were some of the best slides I've ever seen.

[ziggy]

I used to teach at a fullstack bootcamp and I'm completely blown away by the quality of this lecture. Feel like an absolute jabroni. Amazing my dude.

[charliegarrett]

This lecture is just unbelievably good. This guy is a very talented teacher/lecturer

[seyikareem]

This should be a TED Talk, the preparation must have been intense. You Sir are a genius

[SeverityOne]

Less than seven minutes in and I can already see that this is great: clearly explained, well articulated, the works. But now I have to rush off to work, writing lambda expressions in Java.

[mfrdbigolin]

Literally the best talk about lambda calculus on YouTube, after watching this video (and the second one), I am enthusiastic to read To Mock a Mockingbird.

[tauruscolvin]

I’m a long time software engineer. Have been focusing on functional javascript the last couple years. Have been trying to put my finger on why functional feels so much better than other methods. This video and others like it get at it. Functional programming connects to underlying fundamentals such as the lambda calculus and category theory. Fundamentals which transcend a particular language. Functional programming feels like performed art. It’s satisfying again. Symmetrical, elegant, mathematical. I can tell the presenter *feels* the beauty of the lambda calculus too. Thanks for sharing!

[olivierbegassat]

This was remarkably clear, a lot of thought must have gone into preparing this talk ! Thank you so much for this excellent talk : )

[codegeek]

[0:00:00] Intro
[0:00:48] I = a => a
[0:01:48] Notation
[0:06:39] Functions
[0:09:15] Beta-reduction
[0:11:49] M = f => f(f)
[0:15:04] "n-ary" shorthand
[0:17:00] K = a => b => a
[0:18:44] KI = a => b => b
[0:20:49] History
[0:29:30] Combinators?
[0:31:00] C = f => a => b => f(b)(a)
[0:33:46] T = K; F = KI
[0:39:53] not = p => p(F)(T)
[0:42:21] not == C && not !== C
[0:45:30] and = p => q => p(q)(p)
[0:48:39] or = p => q => p(p)(q)
[0:49:29] or == M
[0:51:41] beq = p => q => p(q)(not(q))
[0:54:19] ¬(P ∧ Q) === (¬P) ∨ (¬Q)
[0:55:01] Closing
[0:56:48] Basis
[0:58:15] WHY?
[1:00:37] Y- and Z-Combinators
[1:01:58] Outro

[patrikhagne]

Beautiful talk! I love the way you tie it into javascript, the one functional language that everyone understands!

[aMulliganStew]

Mr. Lebec’s talk was excellent. If I had the desire to return to professional programming, I would be knocking at your door.

[pjnoonan]

This just opened a whole new world to my mind. I can't thank you enough for making and posting this. You can't possibly know how deep my thanks are to the presenter, the staff, and all other associated people. Keep doing what your doing, and you'll find someone will change the world because of your work. Thank you, and bless you all.

[psychedelc]

This probably just saved my midterm grade, 10000x more clear than anything my professor has ever said. Also, this dude looks like the Jeff Winger of logical mathematics

[wingsonthebus]

The prettiest slides I have ever seen.

edit: also some of the most engaging math/programming teaching I have ever been privy to!

[usamakhawaja]

38 minutes into the talk and can't resist to appreciate. Very well explained

[thomasononano]

I'm half way through this, just wanted to praise the speaker and the talk, real quality, perfect for my entry-level FP disposition.

[cashmoneyhustler]

Thank you so much. This is the best YouTube video on the topic. I was lost in the sauce until I watched this