Time+Place: Thursday 20/03/2008 14:30 Room 337-8 Taub Bld.
Title: Computational Awareness
Speaker: Lance Fortnow http://lance.fortnow.com/
Affiliation: Northwestern University
Host: Eldar Fischer

Abstract:


What are we aware of? More than a philosophical pursuit, awareness
plays a crucial role in decision making as one cannot make a choice
that one is not aware of. Billions of advertising dollars are spent in
increasing the awareness of their brands.

Most work on awareness has focused on logical/axiomatic approaches
(for example you are aware of something if you know it or you know you
don't know it). Instead we put awareness through a computational lens,
roughly defining the unawareness of an object as the amount of time it
takes to enumerate that object given the current environment. For
example, if you want to buy a car, the ones you are most aware of are
those which come earlier if you attempted to start enumerating cars.

Based on Levin's "age" function, we give a formal definition of
unawareness using this intuition. The formal definition uses a
universal enumeration as good as any other computable enumeration up
to constant factors. Our definition differs from earlier approaches as
we talk about the awareness of strings as opposed to the truth of some
statement and gives a quantitative measure of unawareness instead of
just a binary awareness/unawareness choice.

We will give some observations on how newer technologies, like search
engines, have affected our awareness of various information, and how
we can become unaware of objects we were once aware of.

We discuss a couple of applications:
- Why do loopholes occur in laws and contracts? We give an explanation
based on the lack of awareness of the legislators of future
circumstances and of the judge's unawareness of what the legislature's
awareness.
- We give a new view of sponsored search auctions based on awareness
and show new bidding strategies when the advertisers wish to increase
awareness of their products.

This talk will cover mostly very preliminary research parts of which
represent joint work with Kim-Sau Chung and Nikhil Devanur.