- From: Jim Hendler <hendler@cs.umd.edu>
- Date: Fri, 13 Jun 2003 06:53:50 -0400
- To: Jeremy Carroll <jjc@hpl.hp.com>, www-webont-wg@w3.org
At 11:34 AM +0300 6/13/03, Jeremy Carroll wrote: >> 1200 seconds (which is admittedly quite a while). > >I would not be unhappy with longer ... > >With these sorts of problems care can often reduce 1200secs to <1sec, the >problem is trying to reduce 1200 years to <1sec. > >Jeremy Jeremy - you need to get over this bizarre affliction -- the time these computations take is often not a feature of the system, but of the PROBLEM. Here's a simple example -- it is trivial to write a little program to play tic-tac-toe in almost any system you give me that can generate instances. On a 3x3 board, you need to store approximately 9!/2 (181,000) instances to enumerate the entire game tree using a naive algorithm. On a 12x12 board this number goes to 144!/2 which is somewhere on the order of 10^240 (give or take a few orders of magnitude) - meaning there is no computer in the world that could come even close to solving this problem in 1200 years. By analogy to your arguments about OWL DL, no language of any type that could encode tic-tac-toe could be decidable, since it could not play 12x12 tic tac toe in any reasonable bounded time - is that correct? -JH -- Professor James Hendler hendler@cs.umd.edu Director, Semantic Web and Agent Technologies 301-405-2696 Maryland Information and Network Dynamics Lab. 301-405-6707 (Fax) Univ of Maryland, College Park, MD 20742 *** 240-277-3388 (Cell) http://www.cs.umd.edu/users/hendler *** NOTE CHANGED CELL NUMBER ***
Received on Friday, 13 June 2003 06:54:06 UTC