Bourbaki listed Grothendieck as a third-generation member. Nevertheless, it does not provide details on when he joined and when he left.
Concerning his departure, there is a Letter from October 9, 1960 and a translation¹
I thank You for your letter², marked by both wisdom and clemency. Indeed it seems pointless that a personal disagreement could be the occasion for the departure of a disciple. I recognize that it was pointless for me to wait for the Master to arbitrate a quarrel that did not concern him and that such arbitration would resolve nothing.
I have asked myself many times over the years of my collaboration with the Master whether my lack of social skill, my impassioned character, and my repugnance for overcoming the repugnance of others, did not render me unsuitable for a productive collaboration during the meetings. No longer wanting to search for the cause anywhere except in myself, I now think that it is better this way and that I reached earlier than the traditional age the moment when I would better serve the Master by my departure, rather than remaining as a result of His kind insistence.
I will endeavor to remain worthy of the teachings that You for so long lavished upon me and not to betray the spirit of the Master who, I hope, will remain visible in my work as it has been in the past.
With this, we can infer the date he left Bourbaki.
Regarding his entrance, It is very likely that he entered with P Cartier, but I cannot prove that. According to Bourbaki that was in 1955.
Is there a reference about when Grothendieck entered Bourbaki?
- By W Messing
- It would be very interesting to know this letter too.