Letters from foreign mathematicians about the context of Brazil in the 1970's

The International Symposium on Dynamical Systems was held in Salvador, in 1971, with the participation of important Brazilian and foreign mathematicians. Steve Smale, distinguished mathematician and winner of the Fields Medal, was one of the speakers at this event. In this paper, we present the letter Paul Koosis wrote to Steve Smale criticizing his trip to Brazil on that political moment; the response letter from Smale, justifying his participation in the event, and the letter in which Mike Shub describes his impressions about the atmosphere in Brazil during the military dictatorship. All the letters were published on the Mother Functor newsletter, a bulletin that circulated in the Department of Mathematics, at University of California-Berkeley. From the letters' information, the purpose is to present the context of mathematical scientific development in Brazil in the mid-1960's and beginning of the 1970's.