Professor Greg Hjorth

Hjorth was part of the talented generation of Australian juniors that grew up during the 1970s. He represented Australia at the 1982, 1984 and 1986 Chess Olympiads, and was also a three-times winner of the prestigious Australian competition the Doeberl Cup, in 1982, 1985 and 1987. Many regarded him as one of the great future talents of Australian chess, but mathematics became his chief focus, limiting his opportunities for tournament play. Over the past 20 years he entered a handful of events in the US, where he was working, and also played in Melbourne upon his recent return to Australia. In his final outing in such a contest, he scored a clean sweep in seven games against strong opposition.

His zenith as a chess champion had come at the Commonwealth Championship at Melbourne in 1983. For all his prodigious brilliance, the 20-year-old Hjorth was regarded as too erratic to compete for high honours, but he went on to share first prize and the title of Commonwealth Chess Champion with the future grandmaster Ian Rogers.

Hjorth had this piece of stern advice for young hopefuls: “If the aim is to have fun, then I would suggest trying not to burst into tears when you lose. If the aim is to become a professional, then if you can’t get into the top 100 by the time you are 21, have a good hard rethink.”

This pronouncement became highly relevant to his own chess progress, when, at the 1984 Commonwealth Championship in Hong Kong, he signally failed to retain the title he had won so brilliantly the year before. He continued to compete on the international chess scene for the rest of that year. He opted for mathematics, even though Fide, the World Chess Federation, had awarded him the title of International Master that very year. By the close of 1984 most of Hjorth’s chess successes already lay behind him.

Gregory Hjorth was born in 1963 in Melbourne. He showed his outstanding abilities from an early age. His interests focused on mathematics, chess, with which mathematical ability is often linked, and philosophy.

He was no believer in what he dismissed as the myth of natural genius, and it was hard work and commitment which marked his approach both to mathematics and to chess — which became a passion at 6, when he and his parents, Robert, a neurologist, and Noela, an artist, were living in London. Having learnt the rules, “there was no stopping him,” his father recalled. The family returned to Australia in the early 1970s and Hjorth attended Preshil and St Michael’s schools in Melbourne. So prodigiously talented was he at mathematics that the story was told of him completing an advanced maths exam so quickly that he fell asleep at the desk and had to be woken to prevent his snoring disturbing more tardy examinees.

Meanwhile, Hjorth began his rapid ascent of the chess heights, his Silver Medal in the 1979-80 Australian championship, when he was 16, heralding the arrival of a big new talent. For decades Australian chess had been dominated by the éminence grise Cecil Purdy, chess teacher par excellence and the first World Correspondence Chess Champion. Purdy, though, had died during a game in Sydney at the age of 73 in 1979. Australian chess was ready for a fresh injection of young blood.

Hjorth’s bachelor’s degree was earned in mathematics and philosophy at the University of Melbourne. This was followed by a PhD at the University of California at Berkeley in 1993, under Professor Hugh Woodin. Hjorth’s thesis was awarded the first Sacks Prize from the Association of Symbolic Logic “for his research in descriptive set theory and its surprising consequences concerning the relationship between set theory and large cardinals”.

Hjorth held a post-doctoral position at Berkeley from 1993-95, when he joined the faculty of the Mathematics Department; he became a full professor in 2005. Since 2006 he spent two quarters of each year at the University of Melbourne, on an Australian Research Council professorial fellowship. He received (with Alexander Kechris) the Association of Symbolic Logic’s Karp Prize in 2003, and was Tarski Lecturer at Berkeley from 2009-10.

Proof is the essence of mathematics, and mathematical knowledge is the most certain knowledge we have. Thus, to those with a philosophical turn of mind, it is the logical foundations of mathematics that are particularly fascinating. Mathematical logic is closely linked to the subject of set theory. Woodin, Hjorth’s doctoral supervisor, is the acknowledged leader in the interplay between the two. The area continues to be a very active one; Hjorth’s work within it focused on a number of themes, including descriptive set theory (it is difficult to describe very highly infinite sets), and large cardinals (used to measure the size of such sets).

Hjorth was a highly productive and creative research mathematician; he wrote more than 60 papers and one book. Dedication to his work and commitment also governed other aspects of his life, including a commitment first to vegetarianism, then veganism, based not on health reasons, but on a refusal to cause suffering to animals.

Hjorth’s personal blog was a curiously wistful compilation, warning his PhD students about the career implications of becoming a professional academic mathematician, not to mention the perils of devoting one’s life to career chess. His blog was conspicuously headed by the ominous, Sioux Indian-inspired observation: “Perhaps today is a good day to die.”

He and his wife, Beth, separated in 2003 after ten years of marriage.

Professor Greg Hjorth, mathematician and International Chess Master, was born on June 14, 1963. He died of a heart attack on January 13, 2011, aged 47