type theory

David Christiansen gives a Strange Loop 2018 introduction to dependent types, where one language serves for both compile-time and run-time code and programs unite with proofs. It draws on his book The Little Typer.

Simon Peyton Jones's first lecture on types in Haskell from the Oregon Programming Languages Summer School 2013. It covers type classes and how they relate to OOP, subtyping and polymorphism.

The Michigan TypeScript group shows the Doom engine running entirely inside the TypeScript type system. It is open source, and two follow-up videos cover why and how they did it.

Philip Wadler's Strange Loop talk on Propositions as Types, the link between logic and computation (the Curry-Howard correspondence). He traces its history through Church, Godel and Turing and shows how it shaped theorem provers and programming languages.

Philip Wadler's Lambda Days talk on propositions as types, the link between logic and computation that underlies theorem provers and programming language design.

A Channel 9 conversation recorded at GOTO 2012 between Anders Hejlsberg (TypeScript) and Lars Bak (Dart). They discuss the two languages and different approaches to making JavaScript development safer, including runtime type checking.

Edwin Brady, creator of Idris, presents Idris 2 and demonstrates type-driven development, where the compiler assists by filling holes and suggesting implementations from types.

Edwin Brady presents Idris 2, a rewrite of the Idris dependently typed language, and shows type-driven development in practice. The demos show the compiler filling in whole functions from their types.

José Valim's ElixirConf US 2023 closing keynote on the foundations of the Elixir type system, covering set-theoretic types and gradual typing with strong arrows.

Aaron Hsu's FnConf18 talk asks whether APL needs a static type system. He argues that APL's expressiveness and rapid iteration already deliver the benefits usually credited to types.

Edwin Brady, creator of Idris, introduces type-driven development in a dependently typed language. He shows types being written first and programs derived with interactive editing, then extends beyond simple examples to programs that interact with users and networks.

A London Haskell talk on the algebra of algebraic data types, showing how sum and product types behave like arithmetic. It frames types as numbers obeying algebraic laws.

ElixirConf EU 2023 talk by Giuseppe Castagna and Guillaume Duboc on bringing set-theoretic types to Elixir, and the benefits such a type system could offer such as catching bugs.

Edward Kmett speaks at the Boston Haskell meetup about type classes and the design tradeoffs of global coherence compared with other approaches to implicit instances. It covers why uniqueness of instances matters for reasoning and refactoring.

Matthias Felleisen's keynote uses weather prediction as an analogy for type systems, arguing they forecast problems so you can act on them. It draws on his experience developing Typed Racket.

Nadia Polikarpova's Strange Loop talk on program synthesis driven by refinement types, as in Synquid. It shows how rich type specifications can be turned into verified, executable code.

An interview with Anders Hejlsberg, lead architect of TypeScript, about porting the TypeScript compiler to Go. He covers the 10x type-checking speedup, lower memory use, and why Go was chosen.

Adam Neely examines Phil Ewell's paper arguing Western music theory is framed by a white racial perspective. He covers North Indian theory, alternative frameworks, Schenker and responses to the paper.

The first lecture in Bartosz Milewski's category theory series for programmers. It covers the motivation and philosophy behind category theory and why composition matters for handling complexity.

Physicist Angela Collier's roughly hour-long video on how string theory was hyped to the public and what that did to science communication. She traces the history of the theory as a narrative and argues it is interesting but was oversold.

Andrew Huang teaches the basics of music theory in about half an hour, covering intervals, chords and patterns. He stresses understanding how music works over memorizing terminology.

The first lecture of David MacKay's Cambridge course on information theory, pattern recognition and neural networks. It introduces the core ideas of his book Information Theory, Inference, and Learning Algorithms.

Eugenia Cheng gives the opening keynote at Lambda World 2017, presenting category theory as very abstract algebra whose abstraction gives it broad applicability. She applies it to everyday questions including privilege and prejudice.

Tom LaGatta's talk on category theory at a 2014 LispNYC meetup, covering objects, morphisms and the basic ideas in an informal, conversational style. It runs about 97 minutes.

Sixty Symbols interviews Nottingham cosmologist Tony Padilla, who says string theory deserves to be taken seriously. He explains how strings emerged from the equations rather than being invented.

CuriousMarc inspects a newly arrived Teletype Model 19, an early military unit built around a Model 15 keyboard and printer, after an initial rough cleaning. It is the first part of a restoration series and touches on 5-bit Baudot code.

3Blue1Brown uses Wordle as an excuse to teach information theory and entropy, building a solver that picks guesses by expected information and incorporating word frequencies.

Erik Meijer argues that category theory is the mathematicians' version of interface-based design. He shows that Java 8 lambdas and method references form a Cartesian closed category.

Professor Brailsford of the University of Nottingham describes how the university set out to print its own mathematics exam papers in the 1980s. The story centers on getting a Mergenthaler Linotron 202 typesetter to work with their own software.

A Ben Heck Show episode tearing down the Nintendo PlayStation prototype, one of the rarest consoles ever, with its owners Terry and Dan Diebold. Part 2 then gets it working again.

A talk by Eric Weinstein on gauge theory and its possible application to economics and inflation. It proposes extending the Wu-Yang dictionary into a geometric tool beyond physics.

Rich Hickey's Clojure/Conj 2018 keynote argues that Maybe/Option types and rigid type signatures are a poor way to model data that changes over time. He builds the case around optionality, schema growth and compatibility, and presents the ideas behind Clojure spec as an alternative.

Jiahao Chen's JuliaCon 2017 talk argues that vector transposes should be taken seriously in type systems and linear algebra libraries. It explains why treating vectors as matrices causes trouble in languages.

Scott Wlaschin shows how statically typed functional languages, using F# examples, can model a business domain so that invalid states cannot be represented. The type system acts almost like an instant unit test at compile time.

Tom 7's pilot episode of a series that plays with type systems and absurd programming, presented as a parody of the GPL v3 license. It mixes a typesetting experiment with a long, story-driven intro on the origin of TeX. Source code and papers are linked from the author's site.

Simon Peyton Jones presents linear types for Haskell, showing how practical linearity can fit into a higher-order polymorphic language. The talk covers motivations such as resource handling and relates the ideas to Rust.

CuriousMarc connects a restored 1930 Model 15 Teletype to a Linux machine and uses it as a terminal, after commenters requested it. The video shows the challenges of linking a 5-bit mechanical device to a modern OS.

3Blue1Brown builds intuition for Euler's formula, e^(pi i) = -1, using the core ideas of group theory. It treats exponentiation geometrically as rotation and scaling instead of repeated multiplication.

The SILE author's FOSDEM 2015 talk introducing SILE, a TeX-inspired typesetting system with frame-based layout, Unicode, OpenType and a Lua-based extensible design.

ScienceClic gives a 15-minute animated introduction to quantum field theory, covering fields, spin, conserved quantities, the standard model and interactions.