Subsequently, Lejeunne Dirichlet
(1805-1859) gave the definition of function which was being used till the set
theoretic definition of function presently used, was given after set theory was
developed by Georg Cantor (1845-1918) The set theoretic definition of function
known to us presently is simply an abstraction of the definition given by Dirichlet
in a rigorous manner Rationalised 2023-24
 18
MATHEMATICS
vMathematics, in general, is fundamentally the science of
self-evident things — FELIX KLEIN v
2