Leonard Euler (1707-1783) gave us a number of symbols. They are listed below.
|f(x)||for functional notation|
|e||for the base of natural logarithms|
|a, b, c||for the sides of triangle ABC|
|for the summation sign|
|i||for the imaginary unit, the square root of -1|
Thomas Harriot (1560-1621), usually considered the founder of the English school of algebraists, was the first to use the signs > and < for "is greater than" and "is less than," respectively.
Gottfried Wilhelm Leibniz (1646-1716) gave us our intersection symbol, , and union symbol, , from set theory.
In 1808 Christian Kramp (1760-1826) of Strassbourg introduced n! for factorial n (or n factorial). The previous symbol was causing printing difficulties.
John Wallis (1616-1703), a mathematician and one of the first to create a system for teaching deaf mutes, introduced our present symbol for infinity .