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Tag: personal


Exactly 20 years ago I wrote my first blogpost, ‘a blogging 2004’. I wasn’t using WordPress yet (but something called pMachine), and this blog was not called ‘neverendingbooks’, but ‘’ (the URL of the mac still running this blog).

At the time I wanted to find out whether blogging was something for me. “I’m just starting out. Give me a couple of weeks/months to develop my own style and topics and I’ll change the layout accordingly.”

Well, after 20 years I know what I can, and more important, what I cannot do within this framework. Time to move on.

There are other reasons why this might be the right time to pull the plug.

– I’m on retirement since October 1st and soon I’ll have to vacate my office, containing the webserver on which NeB runs.

– My days are filled with more activities now, and I don’t think you want to read here for example about my struggles with chestnut-farming.

– I like to explore other channels to talk about mathematics. This may happen on Mathstodon, MathOverflow or YouTube. Or it might be through teaching or writing a book, perhaps even a children’s book.

NeB will remain reachable until mid 2024. I’ll check out options to preserve its content after that (suggestions are welcome).

I wish you a better 2024.



A suit with shorts

I’m retiring in two weeks so I’m cleaning out my office.

So far, I got rid of almost all paper-work and have split my book-collection in two: the books I want to take with me, and those anyone can grab away.

Here’s the second batch (math/computer books in the middle, popular science to the right, thrillers to the left).

If you’re interested in some of these books (click for a larger image, if you want to zoom in) and are willing to pay the postage, leave a comment and I’ll try to send them if they survive the current ‘take-away’ phase.

Here are two books I definitely want to keep. On the left, an original mimeographed version of Mumford’s ‘Red Book’.

On the right, ‘Een pak met een korte broek’ (‘A suit with shorts’), a collection of papers by family and friends, presented to Hendrik Lenstra on the occasion of the defence of his Ph.D. thesis on Euclidean number-fields, May 18th 1977.

If the title intrigues you, a photo of young Hendrik in suit and shorts is included.

This collection includes hilarious ‘papers’ by famous people including

  • ‘A headache-causing problem’ by Conway (J.H.), Paterson (M.S.), and Moscow (U.S.S.R.)
  • ‘A projective plain of order ten’ by A.M. Odlyzko and N.J.A. Sloane
  • ‘La chasse aux anneaux principaux non-Euclidiens dans l’enseignement’ by Pierre Samuel
  • ‘On time-like theorems’ by Michiel Hazewinkel
  • ‘She loves me, she loves me not’ by Richard K. Guy
  • ‘Theta invariants for affine root systems’ by E.J.N. Looijenga
  • ‘The prime of primes’ by F. Lenstra and A.J. Oort
  • (and many more, most of them in Dutch)

Perhaps I can do a couple of posts on some of these papers. It might break this clean-up routine.

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