series(redirected from upper GI series)
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series,in mathematics, indicated sum of a sequencesequence,
in mathematics, ordered set of mathematical quantities called terms. A sequence is said to be known if a formula can be given for any particular term using the preceding terms or using its position in the sequence.
..... Click the link for more information. of terms. A series may be finite or infinite. A finite series contains a definite number of terms whose sum can be found by various methods. An infinite series is a sum of infinitely many terms, e.g., the infinite series 1-2 + 1-4 + 1-8 + 1-16 + … . The dots mean that the remaining terms are formed according to the rule made evident by the first few terms, in this case doubling the denominator of the preceding term to form that of the next term; the nth term of this series is ( 1-2)n. Some infinite series converge to a certain value called its limit; i.e., as one adds together progressively more terms, these sums (called the partial sums of the series) form a sequence of values that progressively approach the limit. For example, the series given above converges to the value 1 because the partial sums form the sequence 1-2, 3-4, 7-8, 15-16, … . Many series, however, do not converge, i.e., have no value that their partial sums approach. Such a series is 1-2 + 1-3 + 1-4 + … , for even though the terms become very small, enough of them added together will give a value greater than any number that can be named. A series that does not converge is said to diverge; various tests exist for determining whether or not a given series converges and for determining its limit if it does converge. See also progressionprogression,
in mathematics, sequence of quantities, called terms, in which the relationship between consecutive terms is the same. An arithmetic progression is a sequence in which each term is derived from the preceding one by adding a given number, d,
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in botany, a taxonomic category intermediate between section and species. The series is the first superspecies category and is usually designated by an adjective in the plural form. Closely related geographic races of plants having a normal sexual cycle of development and a common origin form a species series. The concept of series, which played a notable role in the study of plant species, was elaborated in the early 20th century by V. L. Komarov. Geographic races are united in series not according to morphological data but according to phylogenetic data. Hence, this method provides an idea of the course of evolution and makes it possible to “reconstruct that natural process of differentiation of organisms by means of divergence. … which lies at the basis of the process of species formation” (V. L. Komarov, Izbr. soch., vol. 1, 1945, p. 195).