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What is PLUS times PLUS?

A 28-minute video by 2swap about calculus, computing mechanisms and theory of computation, on the Computer science shelf. It came up in r/compsci, in a thread called “Can someone explain to me lambda calculus?”. It is pitched at intermediate level.

2swap, Video, 28 min, 2025, on the Computer science shelf

Study notes

Intermediate, Derivation. Step 2 of 3 in What computation is

Helpful first

• Functions
• Basic symbolic substitution

What it builds

• Represent numbers and operations as functions.
• Unlearn ordinary data types to see computation as rewriting.
• Follow beta reduction mechanically.

Useful moments

• 0:21Factorial and three as lambda expressions
• 1:19Starting over with lambda calculus
• 6:27Beta reduction

Check yourself: How could a number be represented by the behaviour of a function rather than by a numeral?

Next in the path: Proof That Computers Can't Do Everything (The Halting Problem)

Notes are based on metadata, Reddit context and selected English caption passages. They are not a review of every claim in the video.