From: nates@ll.mit.edu ( Nate Smith)
Newsgroups: rec.games.abstract
Subject: Re: defects in abstract games
Date: 29 Dec 92 16:01:41 GMT
Organization: MIT Lincoln Laboratory

In article <1992Dec28.224523.28467@news.arc.nasa.gov> nicholso@pioneer.arc.nasa.gov (Melvin H. Nicholson YBH) writes:
>First my characterization of what constitutes 'defect free' status[:]
>
>1: state should be limited to position of pieces on the board and whose
>turn it is, with no reference to 'previous board positions' and other
>phenomenon which must be tracked

this does sound like a good criterion.  but the "no repeat" concept
also has a nice sound to it.  repeated positions can occur in games
where pieces move or are removed, but cannot occur in games where
pieces are steadily added to the playing board until the result is
determined.  
>
>2: the rules should not admit special cases and be symmetric to all
>pieces and positions

if this symmetry is a logical symmetry, rather than ruling out
rectangular or other asymmetrical boards.  "what i can do with my
greeblefoy is what you can do with your greeblefoy".
>
>3: the rules should be stable in a concise way, and not too numerous
>
another poster has surmised that you meant to say "statable".  i dont
view that as necessary to being free of defects - you could have
500,000 rules and still be "defect free" i suppose, its just not
desirable!!

the notion of being "stable" is also a good target.  this gets back
into the realm of the mathematical fiction created by the game's
rules.  it must be a stable realm.  if, in the interest of conciseness,
we inadvertantly allow a "leak" in the game-space, this is no good.
if Go was on an infinite board, a shicho (ladder) would destroy the
game, or if there was no rule about a ko....

>While I agree that defect free status isn't all that wonderful of a
>thing (as someone pointed out, tic-tac-toe is quite 'defect free' in
>this since, but in general is a lousy game), I do sympathise with the
>aesthetic quality the original author was trying to put his finger on.

thank you.  :-)
>
>The only interesting games (above the tic-tac-toe level of complexity)
>which I can think of that meet this criterion are Abalone, Reversi, and
>Dots.  There has been enough talk about the games that I don't feel I
>need to repeat their rules, but their simple accounting of score and
>very simple rules which belie their complexity is quite inspiring.
>
>Mel

maybe i could expand this line to the notion of "desirable".
An abstract game becomes more "desirable" when

  1) the number of rules of play is smaller.

  2) the rules of play are freer of defects.

  3) the game is easier to describe to others.

  4) the game is more complex to play.

the description of the playing board (whatever it is, 2-d, 3-d,
all mental, etc.) & playing pieces should also be easy to do.

now i will admit a certain prejudice to pentominoe games, but the
description of the pieces as "the 12 ways to arrange 5 squares joined
by their edges in a 2-d plane" will always need some further elucidation
when you are introducing them to a new player.

if you take the 4th criterion and divide it by the sum of the first 3,
you get a ratio.  i suspect that Go comes out very well with such a
subjective index.  on the other hand, some of the dungeons & dragons
role-playing games get huge in the divisor when getting huge in the
numerator.  or consider the avalon-hill war games with their focus on
simulation over abstract aesthetics.  indeed, simulation, in both of
those kinds of games, is held in high importance.  it has no importance
in abstract games.  using Go strategy in WWII was not appropriate.
simulation will probably always introduce undesirable effects to an
abstract game.

this discussion had been talking about driving number 2 to zero.

- nate
Newsgroups: rec.games.abstract