My father, Dr David Rees, who has died aged 72, was a polymath whose intelligence shone out throughout his life. Dai, as he was known to all, worked at various times as a teacher of maths and statistics, for the Open University, and for the US company National Semiconductor. In the 1980s he settled in Munich, and in 1989 joined the European Patent Office. He worked his way up the organisation, becoming chairman of a board of appeal in 2008.
At the EPO he wrote a decision (G3/08) on the patentability of computer-related inventions. A reference to Lewis Carroll’s Through the Looking Glass in the reasons for the decision was typical of Dai. The decision was well-received, drew worldwide press attention and has its own Wikipedia page.
