Re: [EXTERNAL] Re: Axiom musings...

2020-12-21 Thread Tim Daly
The goal is to prove Axiom algorithms, such as the GCD over the natural numbers, correct using something like Lean. I've studied traditional approaches like Hoare triples but I think there might be a different approach. It depends on Harper's Trinity. Suppose I had a set of verification condition

Re: [EXTERNAL] Re: Axiom musings...

2020-12-18 Thread Tim Daly
Quoting Dijkstra (1988, EWD1036): ... a program is no more than half a conjecture. The other half of a conjecture is the functional specification the program is supposed to satisfy. The programmer's task is to present such complete conjectures as proven theorems. Axiom's SANE research project is

Re: [EXTERNAL] Re: Axiom musings...

2020-12-18 Thread Tim Daly
I occasionally get grief because Axiom is implemented in Common Lisp. People don't seem to like that for some odd reason. Lisp, one of the easiest languages to learn, seems to be difficult to accept. I'm working with John Harrison's book "Practical Logic and Automated Reasoning" from 2009. It uses

Re: [EXTERNAL] Re: Axiom musings...

2020-09-25 Thread Tim Daly
No, the name 'Axiom" is used by many different companies. Trademarks only cover infringement "in the same area" (although the Lexus car company sued a diner named Lexus and "won" because the diner couldn't compete against big corporate lawyer money). One company in New Jersey named their language

Re: [EXTERNAL] Re: Axiom musings...

2020-09-25 Thread William Sit
Axiom Space, a Houston-based company, is not related to Axiom the scientific computation system. Or is it? William William Sit Professor Emeritus Department of Mathematics The City College of The City University of New York New York, NY 10031 homepage: wsit.ccny.cuny.edu ___

Re: [EXTERNAL] Re: Axiom musings...

2020-07-26 Thread William Sit
y.cuny.edu From: Tim Daly Sent: Saturday, July 25, 2020 5:18 AM To: William Sit Cc: axiom-dev Subject: Re: [EXTERNAL] Re: Axiom musings... The further I get into this game, the harder it becomes. For example, equality. In the easiest case Axiom has propositional equality. That is, th

Re: [EXTERNAL] Re: Axiom musings...

2020-07-25 Thread Tim Daly
t;> Too bad we did not continue that effort. Does such a domain (in any >> computer >> algebra system) exist these days? After all, nearly three decades have >> passed. >> >> William >> >> William Sit >> Professor Emeritus >> Department of Mathema

Re: [EXTERNAL] Re: Axiom musings...

2020-07-21 Thread Tim Daly
uter > algebra system) exist these days? After all, nearly three decades have > passed. > > William > > William Sit > Professor Emeritus > Department of Mathematics > The City College of The City University of New York > New York, NY 10031 > homepage: wsit.ccny.cuny.edu >

Re: [EXTERNAL] Re: Axiom musings...

2020-07-21 Thread William Sit
__ From: Tim Daly Sent: Monday, July 20, 2020 4:44 PM To: William Sit Cc: axiom-dev Subject: Re: [EXTERNAL] Re: Axiom musings... > So there are two kinds of algorithms, one that is purely mathematical > and one that is computational, the latter including a particular (class o

Re: [EXTERNAL] Re: Axiom musings...

2020-07-20 Thread Tim Daly
hm handles overflows correctly AND specified in the documentation. > > I am sure I am just being ignorant to pose these questions, because they > must have been considered and perhaps solved. In that case, please ignore > them and just tell me so. > > William > > William Sit &g

Re: [EXTERNAL] Re: Axiom musings...

2020-07-20 Thread William Sit
w York New York, NY 10031 homepage: wsit.ccny.cuny.edu From: Tim Daly Sent: Sunday, July 19, 2020 5:33 PM To: William Sit Cc: axiom-dev Subject: Re: [EXTERNAL] Re: Axiom musings... There are several "problems" with proving programs correct that I don

Re: [EXTERNAL] Re: Axiom musings...

2020-07-19 Thread Tim Daly
There are several "problems" with proving programs correct that I don't quite know how to solve, or even approach. But that's the fun of "research", right? For the data representation question I've been looking at types. I took 10 courses at CMU. I am eyebrow deep in type theory. I'm looking at ca

Re: [EXTERNAL] Re: Axiom musings...

2020-07-19 Thread William Sit
Hi Tim: Glad to hear from you now and then, promoting and working towards your ideas and ideals. >>We need proven algorithms. Just one short comment: it is often possible to prove algorithms (that is, providing the theoretical foundation for the algorithm), but it is much harder to prove tha