Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!bbn!rochester!udel!burdvax!macbeth!lang
From: lang@macbeth.PRC.Unisys.COM (Francois-Michel Lang)
Newsgroups: comp.lang.prolog
Subject: Re: Higher Order Extensions
Message-ID: <10145@burdvax.PRC.Unisys.COM>
Date: 3 May 89 17:26:54 GMT
References: <11500013@hpldola.HP.COM> <783@gould.doc.ic.ac.uk>
Sender: news@PRC.Unisys.COM
Organization: Unisys Corporation, Paoli Research Center; Paoli, PA
Lines: 17

In article <783@gould.doc.ic.ac.uk> cdsm@doc.ic.ac.uk (Chris Moss) writes:
...
>2 points: 
>  1. The predicate to find the set of all solutions can easily be written 
>in pure Prolog with negation. (It's the list of which there are no
>other solutions). The only problem is that it is O(N^2). 

I know how to find the set of all solutions in O(N^2) time
without using assert/retract (a la findall),
but unless we have somewhat different notions of "pure Prolog",
I can't do it completely purely.

How is the pure version of such a predicate written?
----------------------------------------------------------------------------
Francois-Michel Lang
Paoli Research Center, Unisys Corporation lang@prc.unisys.com (215) 648-7256
Dept of Comp & Info Science, U of PA      lang@cis.upenn.edu  (215) 898-9511