Favorite Mathematical Constants

Steven Finch, with the help of many kind friends!

All numbers are not created equal; that certain constants appear at all and then echo throughout mathematics, in seemingly independent ways, is a source of fascination. Just as physical constants provide "boundary conditions" for the physical universe, mathematical constants somehow characterize the structure of mathematics.

The constants listed below are rather arbitrarily organized by topic. You might find an associated table of constants to be more helpful. Here also is an accessible overview of the subject.

I welcome notification (contact information here) of significant references I've missed, errors I've committed or favorite constants I've overlooked.

Well-known constants

Constants associated with Number Theory

Constants associated with Analytic Inequalities

Constants associated with the Approximation of Functions

Constants associated with Enumerating Discrete Structures

Constants associated with Functional Iteration

Constants associated with Complex Analysis

Constants associated with Geometry

Relevant Links