Fermat, Leibniz, Euler, and the gang: The true history of the concepts   of limit and shadow
  Fermat, Leibniz, Euler, and Cauchy all used one or another form of approximate equality, or the idea of discarding "negligible" terms, so as to obtain a correct analytic answer. Their inferential moves find suitable proxies in the context of modern theories of infinitesimals, and specifically the concept of shadow. We give an application to decreasing rearrangements of real functions. 
Tiziana Bascelli, Emanuele Bottazzi, Frederik Herzberg, Vladimir   Kanovei, Karin Katz, Mikhail Katz, Tahl Nowik, David Sher...
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