The paper with Alfred Galichon and Marc Henry, on Local Utility and Multivariate Risk Aversion is now available online on http://papers.ssrn.com/,
"The present paper We
revisit Machina's local utility as a tool to analyze attitudes to
multivariate risks. Using martingale embedding techniques, we show that
for non-expected utility maximizers choosing between multivariate
prospects, aversion to multivariate mean preserving increases in risk is
equivalent to the concavity of the local utility functions, thereby
generalizing Machina's result in Machina (1982). To analyze comparative
risk attitudes within the multivariate extension of rank dependent
expected utility of Galichon and Henry (2011), we extend Quiggin's
monotone mean and utility preserving increases in risk and show that the
useful characterization given in Landsberger and Meilijson (1994) still
holds in the multivariate case"