Ronald Getoor

In the late 1950s, Getoor and Robert Blumenthal set out to understand the work of Gilbert Hunt on the connection between Markov processes and potential theory, extending the connections between Brownian motion and Newtonian potential theory. Getoor's 1968 book Markov Processes and Potential Theory, co-authored with Blumenthal, became a reference on the topic. Together with Blumenthal and Sharpe, Getoor obtained many results on the fine structure of Markov processes and martingales, in particular the theory of local time for Markov processes. With Michael J. Sharpe, Getoor defined the notion of 'conformal martingale', which proved to be influential in potential theory, investigated the behavior of Bessel processes, last-exit times and excursions. Starting in the early 1980s, Getoor studied stationary extensions of a given strong Markov process, with time extending to infinity in both directions, formulating a pathwise view of "time reversal" which became a key tool in his studies of the excessive measures of a Markov process. The 'Blumenthal-Getoor index', a concept which characterises the nature of discontinuities of Lévy processes and semi-martingales, is named after him. ==Personal life==

He married in 1959. His wife Ann Getoor worked on the design of commercial aircraft at Boeing, and his daughter Lise Getoor is a professor of computer science at the University of California, Santa Cruz. Getoor died at home on October 28, 2017, in La Jolla at the age of 88. ==Selected publications==

;Books • • with Robert McCallum Blumenthal: • ;Articles • • • • • • ==References==