We obtain complete asymptotic expansions for certain binomial sums, including the Ape ry numbers. In general, binomial sums cannot be expressed by closed formulae, but they do satisfy polynomial recurrence relations. We use the asymptotic expansion of a binomial sum to calculate a lower bound for th
An Asymptotic Formula for the Commutators
โ Scribed by Daniel Beltita; Mihai Sabac
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 245 KB
- Volume
- 153
- Category
- Article
- ISSN
- 0022-1236
No coin nor oath required. For personal study only.
โฆ Synopsis
In what follows we shall describe some asymptotic formulas for the commutators defined by the values of the analytic functional calculus of some commuting n-tuple of bounded operators in a complex Banach space.
1998 Academic Press Let B(X) be the algebra of all bounded linear operators on a complex Banach space X. For Q and A in B(X) we denote (ad Q) A=[Q, A]= QA&AQ. Related to the invariant subspace problem for certain Lie algebras of operators, in [8,9] occurred the problem of describing properties of the operator ad f (Q) (where f # O(_(Q)) i.e. f is analytic on a neighborhood of _(Q); f (Q) denotes the corresponding value of the analytic functional calculus) in terms of the corresponding properties of ad Q. The complexity of this problem is suggested by the following Taylor type formula announced in [9]:
where \ is a certain positive number depending on Q and T (see Theorem 1 below) and f (n) is the n th derivative of f. Connected to the study of the perturbation topology defined by the spectral semi-distance p in B(X), in [1,2] are proved other Taylor type formulas article no.
๐ SIMILAR VOLUMES
The present article is really a continuation of the author's earlier paper [,l] on this subject. The line of investigation described previously is rounded off by deriving some further numcrical results, which include, in particular, an asymptotic fonnula for the number of complete propositional conn
We obtain a representation formula for the trigonometric sum f (m, n) and deduce from it the upper bound f(m, n) < (4/p 2 ) m log m+ (4/p 2 )(c -log(p/2)+2C G ) m+O(m/`log m), where C G is the supremum of the function G(t) :=; . k=1 log |2 sin pkt|/(4k 2 -1), over the set of irrationals. The coeffi