The principal part at of a function
is the portion of the Laurent series consisting of terms with negative degree. That is,
is the principal part of at . has an essential singularity at, if and only if the principal part is an infinite sum.
Famous quotes containing the words principal and/or part:
“The principal point of cleverness is to know how to value things just as they deserve.”
—François, Duc De La Rochefoucauld (1613–1680)
“I love this child. Red-haired—patient and gentle like her mother—fey and funny like her father. When she giggles I can hear him when he and I were young. I am part of this child. It may be only because we share genes and that therefore smell familiar to each other. . . . It may be that a part of me lives in her in some important way. . . . But for now, it’s jelly beans and “Old MacDonald” that unite us.”
—Robert Fulghum (20th century)