[sci.bio] Lotka-Volterra question

kurtze@plains.NoDak.edu (Douglas Kurtze) (10/31/90)

Does anybody out there know about (or know where I can find out about)
CONTINUUM Lotka-Volterra population models?  By "continuum", I mean that
you take the usual many-species model,

     dP_i/dt = P_i Sum c_ij P_j

and let the species indices i and j be continuous variables (so the sum
over j becomes an integral with a dj).  I can interpret this by letting
the indices label slightly different phenotypes, with P(j)dj being the
number of individuals whose types are within dj of j.  The variables
i and j can be multidimensional.

I encountered the continuum version of this equation a few years ago in
a completely different context -- studying the shape of flames (chemical
ones, not the ones you get here ;-) ) -- and realized that the results I
got could have some application to population dynamics.

Respond by e-mail or post; I do read this newsgroup.  References would be
much appreciated!


Doug Kurtze                   kurtze@plains.NoDak.edu
Physics, North Dakota State

"Patience is its own reward" -- Flann O'Brien

kurtze@plains.NoDak.edu (Douglas Kurtze) (11/01/90)

Gaffe!

In message <6514@plains.NoDak.edu>, in the heat of the moment and the
spirit of late October campaigning, I wrote the Lotka-Volterra equation as

*     dP_i/dt = P_i Sum c_ij P_j

Of course, it should be

     dP_i/dt = r_i P_i - P_i Sum c_ij P_j

Apologies to anybody who will have gotten confused and/or corrected me
before getting this message.  With this correction, the rest of my
previous post is correct.


Doug Kurtze                   kurtze@plains.NoDak.edu
Physics, North Dakota State

"Patience is its own reward" -- Flann O'Brien