Dear Tim You have my deep sympathy. Please convey my condolences to Marcus and Ronnie's family. I will remember the date because 6 Dec is the anniversary of my Father's death in 1969 (at age 58). We can be happy to know that Ronnie saw the recognition and justification of his commitment to groupoids. I was convinced in the 1970s by his innovative book on topology which I used as a text in an honours course at Macquarie. Over the years we became very good friends and colleagues. I visited Ronnie in Bangor and he visited us at Macquarie; these were not just short visits, some were for very memorable conferences. Ronnie showed me over Welsh castles and nature sites on his beloved Anglesey as we talked We had some mildly differing views at times on mathematics. Ronnie alway emphasised the need to be able to calculate, and crossed modules and their variants were good for that. Another pet topic was the van Kampen theorem which he extended using n-tuple groupoids. Once Ronnie said it would be nice for Macquarie to have one of John Robinson's mathematical sculptures. I thought this out of the question because of the cost. However, Ronnie pushed it through. The story is here: https://amusine.typepad.com/journeys/journey.html Well before Zoom, Ronnie was making use of video links. We could give lectures linked live to all the Welsh universities. Ronnie wanted to link with our Australian category seminar but that did not work out because of time differences and the speed of electrons. The point is that Ronnie aimed high! And mostly achieved it, perhaps after some time. It is very sad to lose another great pillar of the categorical community. Ross On 8 Dec 2024, at 5:14 am, Timothy Porter <t.porter.maths@gmail.com> wrote: I have been asked by his son Marcus to inform his friends on the Categories mailing list that Ronnie Brown who was for many years professor at the University College of North Wales (later renamed the University of Bangor) died yesterday at his home in Deganwy. Please share this information with others who may have known Ronnie. Thanks, Tim Porter. You're receiving this message because you're a member of the Categories mailing list group from Macquarie University. To take part in this conversation, reply all to this message. View group files<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.ashx?source=EscalatedMessage&action=files&GuestId=6bf90c14-94d1-45b7-a0b5-9dd447734d27> | Leave group<https://outlook.office365.com/owa/categories@mq.edu.au/groupsubscription.ashx?source=EscalatedMessage&action=leave&GuestId=6bf90c14-94d1-45b7-a0b5-9dd447734d27> | Learn more about Microsoft 365 Groups<https://aka.ms/o365g>