Yes, and another thought. Description as in representing the environment is
one thing, but an underpinning idea in syntax is that of 'description
retrieval' - that is where the structure of society is inscribed in what it
builds and where the form of that society can be retrieved from and
reproduced by the built. It is really this that proposes an answer to how
social forms can last longer than the individuals that compose them and how
these can both be conserved and act to generate new forms. The simple and
general empirical finding of relations between spatial structure and
movement are of interest in that these give rise to patterns of co-presence
between different groups of people, and this offers the mechanism for
description retrieval. The relation to generalisation would seem to me to
refer to the genotypic structures that we retrieve from countless
phenotypes. 

To take an example from your own work on continuity lines. The straight line
of the Edgware Road in London results from a single top down form of
planning (Roman military) whilst the more meandering 'continuity lines' of
West End Lane or the Balls Pond Road, both of which you find with your
analysis as long alignments, result from a previous rural road system
influenced by topography and land ownership parcels in a much more bottom up
fashion. Hypothesis: you would retrieve the results of a centralised planned
society with a lower threshold on angular deviation from the axial map than
for a more distributed form of society... Of course this relates to long and
short model systems in terms of how long the 'rule' must be to obtain the
genotypic outcome. Getting lines straight require planning, engineering and
power - long model. Continuity lines are easier to achieve - shorter model -
but still imply global coordination, an economy that involves long distance
movement of people and goods etc. A very short continuity lines system would
imply less global social coordination and a shorter model still. The link to
a cognitive mechanism in description retrieval looks possible...

Alan

> 
> Lucas
> After 40 years in mathematics I have come to understand that
> generalisation
> comes after a process of something akin to description and in many cases
> where we see examples of very succinct formalism it is really the result
> of
> many examples and exercises in a "descriptive" environment.
> 
> Perhaps the answer lies in the interpretion of deductive -V- inductive
> reasoning.  Maybe some highly motivated student should investigate an
> axiomatic system that would be dedicated to underpinning both the
> philosophy
> and application od SS.
> 
> Tony Donegan
> 
> Dr HA Donegan
> Reader (Mathematics Division)
> School of Computing and Mathematics
> University of Ulster
> Jordanstown
> BT37 0QB
> 
> Tel: 028 90 366589 or 90 366841
> ----- Original Message -----
> From: "Lucas Figueiredo" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Monday, June 04, 2007 6:45 PM
> Subject: Description and Generalisation
> 
> 
> > Dear Colleagues,
> >
> > I am writing something and I stuck in an important question. Space
> > Syntax has been born as 'descriptive theory', supporting the theory of
> > the social logic of space.
> >
> > Axial lines and convex polygons were proposed to describe space in one
> > and two dimensions. Decomposing a continuous system of open spaces
> > into recognisable objects and establishing their elementary relations
> > (Hillier and Hanson 1984, p52).
> >
> > On the other hand, 'Generalisation' is a process of attenuating a
> > spatial patterns while retaining its most important characteristics. I
> > thought that generalisation requires a previous description, but
> > apparently some authors believe that generalisation itself is a tool
> > for describing and analysing cities - therefore there is no necessity
> > to mention space syntax.
> >
> > If this is correct, another consequence is that 'continuity lines' are
> > undertood as a result of generalisation process, therefore they could
> > not ever be proposed as an 'descriptive entity' as I have done, based
> > on axial lines.
> >
> > I used to undertand that generalisation could be used to formalise the
> > creation of 'descriptive entities' for space syntax techniques. On the
> > other hand, space syntax techniques could be used help generalisation,
> > as pointed by WA Mackaness in the past, or Robert Thomson recently.
> >
> > I might be wrong. Is space syntax a subcase of generalisation?
> >
> > Any thoughts?
> >
> > Best Regards,
> > --
> > Lucas Figueiredo
> >
> > Mindwalk
> > http://www.mindwalk.com.br
> >
> >