Digital Chalk - Nathan Doing Topology PhD Qualifying Exam Problems (Live)

 ... on some sort of pen-tablet. It's almost legible on my phone. No pretty colors though, ...

They don't like circular reasoning at UTexas! 


The next problem:


He does explain that a path is some function from the unit interval [0,1] to points in X, so I guess it takes 0 to x and 1 to y and for points in between it traces out the (presumably continuous) path in X, ...


Subscribe to Chalk.

Here's the video about Lawvere's fixpoint theorem:

See also N.S. Yanofsky, A Universal Approach to Self-Referential Paradoxes.

Subscribe to Nicolaj-K.

Comments

Post a Comment

Popular posts from this blog

Live Science - Leonardo da Vinci's Ancestry

Image
... and his posterity too? See  On Communication in Linear Time And Hypertext And The Gospel of Sophia . So it looks like El Cielo of the cistine [sic!😂] chapel is not the limit anymore.  I think I just met one of his descendents. A guy called Versailles Toledo who is from Chiapas. That might explain the murals I mention in my recent untitled post , just before the post mentioning this video. I also just took this photo of Rafael Gonzales, born here in Tecate, B.C., who told me about a spring near here called Agua Fría , half way from Tecate to Loma Tova , where, a few decades ago, people used to go to have barbecues and stuff, but now he thinks it may be private land. If someone reading this has a Facebook account, please write a link to this post onto his FB page. To see why I took the photo, look at his T-shirt and the horse-shoes and ponder this: Subscribe to BeatrizER and her video(s?) about mathematical logic, ... Sounds like Edith (II) Rix has been online all the time, ...
Read more

David Turner Obituary by Sarah Nicholas Fri 24 Nov 2023

Image
This was in The Guardian: David Turner obituary , only eight days after I posted  David Turner Talking About Sixty Years of Functional Programming History : This talk was given in London in 2017: See  Turner, D. A. "Some History of Functional Programming Languages" also  John Hughes - Why Functional Programming Matters  and David MacQueen's talk at ICFP 2015 in  Numberphile - Sophie Maclean on the Catalan Numbers . At 10:30 This whole discussion abut combinator reduction is especially interesting. I didn't know Arthur Norman had tried building hardware for combinator machines. I'll look that up: maybe start here A.C. Norman  Faster combinator reduction using stock hardware  in LFP '88: Proceedings of the 1988 ACM conference on LISP and functional programming. At 26:25 on the ISWIM virtual machine implemented in the PAL compacting garbage collector?! This work Reynolds and others did was at MIT in Masecheusetts and Argonne National Laboratory Illinois. Did
Read more