Functor Fact
@FunctorFact
Followers
26K
Following
41
Media
204
Statuses
4K
Functional programming and category theory tweets from @JohnDCook
Houston, TX
Joined June 2016
Category theory turns math inside-out: Definitions depend on nothing inside, but on everything outside.
0
3
10
The glass disk game (homological algebra)
johndcook.com
Removing all the mathematical content of the five lemma and friends, visualizing the lemmas as a game with glass disks.
0
0
7
'Roughly speaking, homological algebra is concerned with the question of how much modules differ from being projective, injective, or flat.' -- M. Scott Osborne.
0
1
11
“It should be observed first that the whole concept of a category is essentially an auxiliary one; our basic concepts are essentially those of a functor and of a natural transformation.” — S. Eilenberg and S. Mac Lane.
0
1
17
Universal properties are a fairly big conceptual hurdle to get over. But they all have the same flavor: there exists an object and a morphism such that everything factors uniquely through that object.
0
1
14
'When people say 'but most business logic bugs aren’t type errors,' I just want to show them how to make bugs into type errors.' -- Matt Parsons.
0
2
13
Mathematica package for category theory:
wildcatsformma.wordpress.com
The premiere Mathematica package for computational Category Theory
0
2
6
Can construct a fixed point M for a lambda term L by defining M = (λx.L(xx))(λx.L(xx)).
0
0
2
Every lambda term L has a fixed point, a term M such that LM is β-convertible to M.
0
0
4
F* is an ML-like functional programming language aimed at program verification.
0
0
5
'A language that doesn't affect the way you think about programming isn't worth knowing.' -- Alan Perlis.
0
3
11
