Old Hollywood: Lewis sensationally revealed in her 1994 memoir that she was conceived in 1935 when Loretta Young, 22, and the married Clark Gable, 34, were shooting The Call of the Wild. Secret: Loretta Young is pictured with Judy Lewis in 1944, who did not know for years who her father was.
The sigma symbol provides the character used to denote the sum of an equation in mathematics. You can create a sigma sign by accessing the Character Palette, using a keyboard shortcut or by using the Special Characters menu in your current application.
Key Points. 1  A series is a summation performed on a list of numbers. Each term is added to the next, resulting in a sum of all terms. 2  Sigma notation is used to represent the summation of a series. In this form, the capital Greek letter sigma $\left ( \Sigma \right )$ is used. The range of terms in the summation is represented in numbers below and above the $\Sigma$ symbol, called indices.