In 1989, Bob Thomason left his CNRS position in Orsay and moved to Paris VII. It was during this period that he composed his "Open Letter" to the mathematical community. The letter explained Thomason's reasons for leaving the United States.

I lost my copy of this letter many years ago.

Would someone be willing to share with me their copy?

Thanks in advance.

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    $\begingroup$ Some biographic information: math-info-paris.cnrs.fr/bibli/… $\endgroup$
    – YCor
    Oct 1, 2021 at 13:22
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    $\begingroup$ Why are people voting to close this question? The OP did not ask others to comment on the content of the letter. He simply wants a copy of the letter, and asking the MO community seems like a pretty reasonable move. $\endgroup$ Oct 1, 2021 at 16:30
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    $\begingroup$ Further to what @HailongDao says — there are plenty of well-received questions asking for help tracking down difficult-to-find documents in the mathematical literature. So this seems pretty clearly on-topic to me. $\endgroup$ Oct 1, 2021 at 16:43
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    $\begingroup$ @Carlo Beenakker: Actually the OP is right, Thomason spent a few years in Orsay before moving to Paris 7 — I don't remember exactly how many. For instance in the famous Thomason-Trobaugh paper in the Grothendieck Festschrift he gives his address in Orsay. $\endgroup$
    – abx
    Oct 1, 2021 at 18:04
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    $\begingroup$ @CarloBeenakker yes, I know I’m right, as I was in contact with Bob Thomason during this period! $\endgroup$
    – John Klein
    Oct 1, 2021 at 18:09

2 Answers 2


A copy of Thomason's open letter to the mathematical community can be found here.

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    $\begingroup$ it saddens me to read this letter. $\endgroup$ Aug 25, 2023 at 11:29

Because a link to the original letter has been posted, I have posted here, for historical completeness, a link to the handwritten followup letter that Thomason sent out to the same mailing list a few days later.

Edited to add: To be more precise about the timing:

  • The original letter is not dated, but the postmark on the envelope is from February 13, 1991.
  • The followup letter has (at least in my case) an illegible postmark on the envelope, but the letter itself is dated February 22, 1991.

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