sums up
91Direct sum of groups — In mathematics, a group G is called the direct sum of a set of subgroups {Hi} if each Hi is a normal subgroup of G each distinct pair of subgroups has trivial intersection, and G = <{Hi}>; in other words, G is generated by the subgroups… …
92Egyptian fraction — An Egyptian fraction is the sum of distinct unit fractions, such as frac{1}{2}+ frac{1}{3}+ frac{1}{16}. That is, each fraction in the expression has a numerator equal to 1 and a denominator that is a positive integer, and all the denominators… …
93Hardy–Littlewood circle method — In mathematics, the Hardy–Littlewood circle method is one of the most frequently used techniques of analytic number theory. It is named for G. H. Hardy and J. E. Littlewood, who developed it in a series of papers on Waring s problem. Contents 1… …
94Sylvester's sequence — In number theory, Sylvester s sequence is a sequence of integers in which each member of the sequence is the product of the previous members, plus one. The first few terms of the sequence are::2, 3, 7, 43, 1807, 3263443, 10650056950807,… …
95Ramanujan's sum — This article is not about Ramanujan summation. In number theory, a branch of mathematics, Ramanujan s sum, usually denoted c q ( n ), is a function of two positive integer variables q and n defined by the formula:c q(n)=sum {a=1atop… …
96Gauss sum — In mathematics, a Gauss sum or Gaussian sum is a particular kind of finite sum of roots of unity, typically: G ( chi;, psi;) = Sigma; chi;( r ) psi;( r )where the sum is over elements r of some finite commutative ring R , psi;( r ) is a group… …
97Summation of Grandi's series — General considerationstability and linearityThe formal manipulations that lead to 1 − 1 + 1 − 1 + · · · being assigned a value of 1⁄2 include: *Adding or subtracting two series term by term, *Multiplying through by a scalar term by term, *… …
98Modes of convergence — In mathematics, there are many senses in which a sequence or a series is said to be convergent. This article describes various modes (senses or species) of convergence in the settings where they are defined. For a list of modes of convergence,… …
99Ordinal collapsing function — In mathematical logic and set theory, an ordinal collapsing function (or projection function) is a technique for defining (notations for) certain recursive large countable ordinals, whose principle is to give names to certain ordinals much larger …
100Riemann hypothesis — The real part (red) and imaginary part (blue) of the Riemann zeta function along the critical line Re(s) = 1/2. The first non trivial zeros can be seen at Im(s) = ±14.135, ±21.022 and ±25.011 …
