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Enumerating the Rationals

Jeremy Gibbons, David Lester and Richard Bird (2004). Enumerating the Rationals. May 2004.

In this paper,we explain an elegant technique for enumerating the positive rationals without duplicates. Moreover, we show how to do so as a simple iteration, generating each element of the enumeration from the previous one alone,with constant cost per element (assuming unit cost for simple operations on arbitrary-precision rationals). Best of all, the resulting program is extremely simple...

Cute. Nothing earth shattering, but fun none the less.

By Ehud Lamm at 2004-06-29 08:09 | Functional | 10 comments | other blogs | 11789 reads

Nets: Petri vs Lafont

I am currently playing with an idea of a PL based on Petri nets (place/transition nets) augmented with Prolog-like unification.
It just occurred to me that though PNs may be cognitively good for many developers (they express static topology of the system explicitly), Interaction nets may be more suitable for expressing some dynamic features.
I was trying to find any papers on relationship between Petri nets and Interaction nets, but found only indirect link through linear logic.
Is anyone aware of theoretical possibilities to (bi)simulate PNs with INs?
Or any other result about their comparative expressiveness?

By Andris Birkmanis at 2004-06-29 09:25 | LtU Forum | 9 comments | other blogs | 9916 reads

Departments

By Anton van Straaten at 2004-06-29 23:45 | other blogs | 173750 reads