Monogenic function explained

A monogenic[1] [2] function is a complex function with a single finite derivative. More precisely, a function

f(z)

defined on

A\subseteqC

is called monogenic at

\zeta\inA

, if

f'(\zeta)

exists and is finite, with:f'(\zeta) = \lim_\frac

Alternatively, it can be defined as the above limit having the same value for all paths. Functions can either have a single derivative (monogenic) or infinitely many derivatives (polygenic), with no intermediate cases. Furthermore, a function

f(x)

which is monogenic

\forall\zeta\inB

, is said to be monogenic on

B

, and if

B

is a domain of

C

, then it is analytic as well (The notion of domains can also be generalized in a manner such that functions which are monogenic over non-connected subsets of

C

, can show a weakened form of analyticity)

Monogenic term was coined by Cauchy.[3]

Notes and References

  1. Web site: Monogenic function . Encyclopedia of Math . 15 January 2021.
  2. Web site: Monogenic Function. Wolfram MathWorld . 15 January 2021.
  3. Book: A history of analysis . 2003 . American Mathematical Society ; London Mathematical Society . 978-0-8218-2623-2 . Jahnke . H. N. . History of mathematics . Providence, RI : [London] . 229.