Results 231 to 240 of about 77,438 (264)

CONSTANTS OF DERIVATIONS OF PRIME RINGS

Mathematics of the USSR-Izvestiya, 1982
A Galois correspondence theorem is proved for any finite-dimensional Lie -algebra of outer derivations of a prime ring of positive characteristic. A theorem is proved on the existence of a locally finite ideal, in the sense of Sirsov, over the ring of constants of such a Lie -algebra. Extension and rigidity theorems are also obtained.
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On the Graded Ring of Theta-Constants

American Journal of Mathematics, 1964
Introduction. Let g be a positive integer and let T be a complex symmetric matrix of degree g with a positive-definite imaginary part. The set of such matrices forms a convex open subset of the 1 * g (g + 1) -dimensional complex vector space and (as a complex manifold) it is called the Siegel upper-half plane of degree (or "genus") g.
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Rings of Eventually Constant Sequences

Journal of Mathematical Sciences, 2003
All rings are assumed to be associative and to have non-zero identity elements. Throughout \(A\) is a ring with Jacobson radical \(J(A)\), \(B\) is a unitary subring in \(A\), \(\{A_i\}_{i=1}^\infty\) is a countable set of copies of \(A\), \(D\) is the direct product of all the rings \(A_i\), \(B'\) is the subring \(\{(b,b,\dots)\mid b\in B\}\) of \(D\)
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The sharp constant in the ring lemma

Complex Variables, Theory and Application: An International Journal, 1997
In his paper [2] Lowell J. Hansen found a (nonlinear) recurrence formula for the (sharp constant appearing in the “Ring Lemma” of Rodin and Sullivan [3]. In the following we improve Hansen's result and replace his recurrence relation by a linear recurrence formula leading to a closed formula for the Ring Lemma constant.
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Numerical estimates for a Grötzsch ring constant

Constructive Approximation, 1988
The paper studies the behavior of the modulus \(M_ n(a)\) of the Grötzsch extremal ring \(R_{G,n}(a)\subset {\mathfrak R}^ n\) as a tends to 0. In the first two parts lower and upper estimates are obtained for \[ \lim_{a\to 0}(M_ n(a)+\log a). \] The lower estimates are given in terms of n; the upper estimates are obtained numerically for \(3\leq n\leq
Anderson, G. D., Frame, J. S.
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Graded Rings of Theta Constants

1972
Let z → θm(τ, z) denote the familiar theta function on Cg;; we recall that m = (m′m″) is in R2g and τ in 𝔖g. If m is in Q2g, we call θm(τ, 0) a theta constant. Since in this chapter we shall mainly consider theta constants rather than theta functions, we make an agreement that θm means the function τ → θm(τ, 0) on 𝔖g; accordingly, we shall write θm(τ ...
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Constant Volume Ring Shear Apparatus

Geotechnical Testing Journal, 1996
Abstract The paper describes a constant volume ring shear apparatus that allows the measurement of the undrained peak and residual shear strengths of cohesive soils. The undrained peak and residual strengths are applicable to seismic stability evaluations of slopes comprised of or founded on cohesive soil.
TD Stark, IA Contreras
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Shirshov finiteness over rings of constants

Algebra and Logic, 1997
The author studies rings of constants for restricted differential Lie algebras acting on prime rings and having nontrivial quasi-Frobenius inner part. It is shown that, under this restriction, Shirshov's local finiteness correspondence exists between a given prime ring \(R\) and the ring of constants \(R^L\).
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Remarks on rings of constants of derivations II

Communications in Algebra, 1992
Let k be a field of characteristic p>0 and D≠0 a family of k-derivations of k[x,y]. It is proved in [1] that k[x,y]D, the ring of constants with respect to D, can be generated, as a k[x p,y p]-algebra, by p - 1 elements. In this note we prove that p - 1 is the sharp upper bound of numbers of generators.
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Locally nilpotent derivations and their rings of constants.

2009
Given a UFD R containing Q , we study R-elementary derivations of B = R[Y1,..., Ym], i.e., R-derivations satisfying D( Yi) ∈ R for all i; in the particular case of m = 3, we will show that if R is a polynomial ring in n variables over a field k (of characteristic zero), and a1, a3, a3 ∈ R are three monomials, then the kernel of the derivation i=13ai6 ...
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