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 office of history I take to be this: to prevent virtuous actions from being forgotten, and that evil words and deeds should fear an infamous reputation with posterity.”
—Tacitus (c. 55–c. 120)
“Almost always tradition is nothing but a record and a machine-made imitation of the habits that our ancestors created. The average conservative is a slave to the most incidental and trivial part of his forefathers’ glory—to the archaic formula which happened to express their genius or the eighteenth-century contrivance by which for a time it was served.”
—Walter Lippmann (1889–1974)