The notion of a ``market'' has undergone a paradigm shift with the
Internet -- totally new and highly successful markets have been defined
and launched by companies such as Google, Yahoo!, Amazon, MSN and
Ebay. Another major change is the availability of massive computational
power for running these markets in a centralized or distributed manner.

In view of these new realities, the study of market equilibria, an
important, though essentially non-algorithmic, theory within
Mathematical Economics, needs to be revived and rejuvenated via an
inherently algorithmic approach. Such a theory should not only address
traditional market models but also define new models for some of the new
markets.

We present a new, natural class of utility functions which allow buyers
to explicitly provide information on their relative preferences as a
function of the amount of money spent on each good. These utility
functions offer considerable expressivity, especially in Google's
Adwords market. In addition, they lend themselves to efficient
computation, while still possessing some of the nice properties of
traditional models.


This talk is based on the following paper:

http://www-static.cc.gatech.edu/fac/Vijay.Vazirani/spending.pdf