  In this survey, we present in a unified way the categorical and syntactical
settings of coherent differentiation introduced recently, which shows that the
basic ideas of differential linear logic and of the differential
lambda-calculus are compatible with determinism. Indeed, due to the Leibniz
rule of the differential calculus, differential linear logic and the
differential lambda-calculus feature an operation of addition of proofs or
terms operationally interpreted as a strong form of nondeterminism. The main
idea of coherent differentiation is that these sums can be controlled and kept
in the realm of determinism by means of a notion of summability, upon enforcing
summability restrictions on the derivatives which can be written in the models
and in the syntax.
