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:
“There are three principal means of acquiring knowledge available to us: observation of nature, reflection, and experimentation. Observation collects facts; reflection combines them; experimentation verifies the result of that combination. Our observation of nature must be diligent, our reflection profound, and our experiments exact. We rarely see these three means combined; and for this reason, creative geniuses are not common.”
—Denis Diderot (1713–1784)
“There is an inner world; and a spiritual faculty of discerning it with absolute clearness, nay, with the most minute and brilliant distinctness. But it is part of our earthly lot that it is the outer world, in which we are encased, which is the lever that brings that spiritual faculty into play.”
—E.T.A.W. (Ernst Theodor Amadeus Wilhelm)