Principal Part

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)

    “The morning, which is the most memorable season of the day, is the awakening hour. Then there is least somnolence in us; and for an hour, at least, some part of us awakes which slumbers all the rest of the day and night.”
    —Henry David Thoreau (1817–1862)