Re: what is "stretchability" exactly?

[Mark Polesky]

Joe Neeman wrote:
>> NR 4.1.2 "Page formatting" defines stretchability as "the
>> ease with which the stretchable space increases when a
>> page is stretched."  Can anyone provide a more technical
>> quantified explanation?
>
> We space systems by simulating ideal springs (more or
> less).  Stretchability is the inverse of the spring
> constant in Hooke's law.  A reasonable default is
> stretchability = space, because it keeps the proportions
> constant (assuming there are no collisions).

Yikes!  Hmm, this probably won't help the non-physics majors
among our program users...  (:  Is there some way to
identify, for example, the largest meaningful value for
stretchability, as a function of the other variables
involved (whatever they may be), in a reasonably typical
range of cases?

I mean, if I double the stretchability value, the space will
stretch "twice as easily"?  What does that mean?  If I want
the space to stetch "effortlessly", should I set the value
to +inf.0?  And how should I expect the space to behave when
it's stretching "effortlessly"?  This is all so abstract to
me...

- Mark