I've been hoping for a nice concrete example of braided monoidal categories for ages, who knew that the best one was string diagrams that represent actual string! Great post!
@the author - I assume you're aware that morphisms in symmetric monoidal categories can be represented using cospans of hypergraphs - do you know if there's a similar combinatorial representation for braided monoidal categories?
Back in the 1980s I was taking a foundational computer science course in which we derived Goedel's result using Cantor diagonalization. Excellent course. We were watching the TV version of Hitchhiker's Guide to the Galaxy at the time, too. One day I had the realization that since any recursively enumerable function could be interpreted as a computer program (given the right interpreter), that the sweater I was wearing was in fact possibly a computer program, and that all knitting (and some crocheting) was in fact just a manifestation of code in another language.
I then went on to realize any enumerable set could be similarly interpreted, including the entire countable population of Earth. And we already had the answer (42), but what was the question?
I suppose if nothing else, you could encode Wang tiles (https://en.wikipedia.org/wiki/Wang_tile) into knitting and then that's Turing-complete? Or would there be some better CA to encode?
42 is a stand in for 41 and 43 which are some twin prime
for me to further elaborate on this crazy idea that haunts me (I must admit I also haunt these ideas) requires a twin prime theorem which we are still waiting for in 2025....
Does anyone know a good emulator for knitting machines? I'd love to play with these programs, but I'd like to get some practice before I start messing with real wool.
Someone else mentioned the acrylic, I'm going to mention Scarlett Sparks' Open Source Knitting Machine if part of the fear is actually investing in the machine
https://github.com/ScarlettSparks/KnittingMachine
Possibly off-topic, but if you're looking to reduce your costs you should look at acrylic yarn. There's also cotton yarn if you're looking for something less scratchy :)
Still kicking myself for not buying a "3D Knitted Chisel Roll" back when Lee Valley had them --- last I checked it might have been possible to import one from Europe, but having a hard time justifying that.....
That also links to an older piece about a software project for knitting machines that's really neat. I've been wondering for a while how difficult it would be to build a primitive one at home.
...as demonstrated by the analogy in the original post here, where he explains the concrete concept of knitting stitches by reference to the much more abstract concept of garbage collection in computer programming!
I've been hoping for a nice concrete example of braided monoidal categories for ages, who knew that the best one was string diagrams that represent actual string! Great post!
@the author - I assume you're aware that morphisms in symmetric monoidal categories can be represented using cospans of hypergraphs - do you know if there's a similar combinatorial representation for braided monoidal categories?
Braid groups are really interesting, and they also come up in fluid mixing: https://people.math.wisc.edu/~thiffeault/talks/gordon2022.pd...
The slides are a blast, thanks
Classic mathematicians!
Reminds me of the work in the Carnegie Melon Textile Lab on the semantics and scheduling for knitting machine compilers (https://textiles-lab.github.io/publications/2023-knitout-sem...)
"This work is in part a collaboration with folks currently and previously at CMU, including Jenny Lin, Tom Price, Jim McCann, and Hannah Fechtner."
Back in the 1980s I was taking a foundational computer science course in which we derived Goedel's result using Cantor diagonalization. Excellent course. We were watching the TV version of Hitchhiker's Guide to the Galaxy at the time, too. One day I had the realization that since any recursively enumerable function could be interpreted as a computer program (given the right interpreter), that the sweater I was wearing was in fact possibly a computer program, and that all knitting (and some crocheting) was in fact just a manifestation of code in another language.
I then went on to realize any enumerable set could be similarly interpreted, including the entire countable population of Earth. And we already had the answer (42), but what was the question?
I suppose if nothing else, you could encode Wang tiles (https://en.wikipedia.org/wiki/Wang_tile) into knitting and then that's Turing-complete? Or would there be some better CA to encode?
sorry, 42 is not gonna take us much farther
42 is a stand in for 41 and 43 which are some twin prime
for me to further elaborate on this crazy idea that haunts me (I must admit I also haunt these ideas) requires a twin prime theorem which we are still waiting for in 2025....
Does anyone know a good emulator for knitting machines? I'd love to play with these programs, but I'd like to get some practice before I start messing with real wool.
Someone else mentioned the acrylic, I'm going to mention Scarlett Sparks' Open Source Knitting Machine if part of the fear is actually investing in the machine https://github.com/ScarlettSparks/KnittingMachine
Possibly off-topic, but if you're looking to reduce your costs you should look at acrylic yarn. There's also cotton yarn if you're looking for something less scratchy :)
Still kicking myself for not buying a "3D Knitted Chisel Roll" back when Lee Valley had them --- last I checked it might have been possible to import one from Europe, but having a hard time justifying that.....
Speaking of computational knitting, I recently learned about "solid knitting" [1] which is awesome.
https://www.cs.cmu.edu/news/2024/solid-knitting
That also links to an older piece about a software project for knitting machines that's really neat. I've been wondering for a while how difficult it would be to build a primitive one at home.
https://www.cs.cmu.edu/news/2018/software-automatically-gene...
the formalization of textile programming really brings computer science full-circle. as a neoluddite i approve
...as demonstrated by the analogy in the original post here, where he explains the concrete concept of knitting stitches by reference to the much more abstract concept of garbage collection in computer programming!