Michael Brennan obituary

My friend Michael Brennan, who has died aged 80, was a teacher and activist, and also tried to unravel the mathematical basis of Celtic interlace – the ornamental knot patterns found in Irish art.As a youth Mike had assisted his father in his work as a monumental sculptor. He was fascinated by the mathematical forms embedded in Celtic interlace, and in 2004 embarked on a serious study of this field, finally completing a PhD at Bangor University in 2011, on the Structure of Interlace in Ins