Monday, September 01, 2008

Bereavement in Italian Theoretical Computer Science

On the night between August 19 and August 20, Italian TCS prematurely lost Stefano Varricchio (University of Rome "Tor Vergata") while he was on holiday with his family. He was 48, or so I am told.

Stefano's research was in the classic areas combinatorics on words, automata theory and formal languages. I am not qualified to offer an assessment of his research contributions, and I hope that some of my readers who work on the aforementioned topics will post comments on Varricchio's work. I met him once a few years ago during a visit to the University of L'Aquila, where he was a full professor at the time. I recall that, after my presentation based on this paper, he kindly pointed out the relevance of a famous theorem by Fine and Wilf for some of the results I presented.

Here is the theorem.

Theorem (Fine and Wilf, 1965) If a word x has periods p and q, and has length at least p + q − gcd(p, q), then x has also a period gcd(p, q).

A relative of mine and his wife, who followed Stefano's compilers course in L'Aquila, told me that he was one of the best teachers they had during their studies.

To quote a poem by Giuseppe Ungaretti,
Si sta come, d'autunno, sugli alberi, le foglie.
G. Ungaretti - Soldati Bosco di Courton luglio 1918

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