共查询到20条相似文献,搜索用时 15 毫秒
1.
Zbigniew S. Marciniak Sudarshan K. Sehgal 《Proceedings of the American Mathematical Society》1998,126(2):343-348
Let be an arbitrary group. If satisfies , , then the units , generate a nonabelian free subgroup of units. As an application we show that if is contained in an almost subnormal subgroup of units in then either contains a nonabelian free subgroup or all finite subgroups of are normal. This was known before to be true for finite groups only.
2.
Every complete doubling metric space carries a doubling measure 总被引:4,自引:0,他引:4
We prove that a complete metric space carries a doubling measure if and only if is doubling and that more precisely the infima of the homogeneity exponents of the doubling measures on and of the homogeneity exponents of are equal. We also show that a closed subset of carries a measure of homogeneity exponent . These results are based on the case of compact due to Volberg and Konyagin.
3.
U. Meierfrankenfeld 《Proceedings of the American Mathematical Society》1998,126(2):353-356
Let be a group, a division ring and a -module. is called finitary provided that is finite dimensional for all . We investigate the first and second degree cohomology of finitary modules in terms of a local system for .
4.
M. B. Bekka 《Proceedings of the American Mathematical Society》1998,126(2):507-514
The following results on uniqueness of invariant means are shown:
(i) Let be a connected almost simple algebraic group defined over . Assume that , the group of the real points in , is not compact. Let be a prime, and let be the compact -adic Lie group of the -points in . Then the normalized Haar measure on is the unique invariant mean on .
(ii) Let be a semisimple Lie group with finite centre and without compact factors, and let be a lattice in . Then integration against the -invariant probability measure on the homogeneous space is the unique -invariant mean on .
5.
Sheng Wang Wang 《Proceedings of the American Mathematical Society》1998,126(2):453-460
We introduce two operations , in the set of subgenerators of a given - regularized semigroup and prove that is a complete partially ordered lattice with respect to , and the operator inclusion . Also presented are some other properties and examples for
6.
Let be a finitely generated non-PI Ore domain and the quotient division algebra of . If is the center of , then .
7.
Saban Alaca 《Proceedings of the American Mathematical Society》1998,126(7):1949-1953
A -integral basis of a cubic field is determined for each rational prime , and then an integral basis of and its discriminant are obtained from its -integral bases.
8.
N. Bertoglio Servet Martí nez Jaime San Martí n 《Proceedings of the American Mathematical Society》1998,126(2):375-382
For a self-adjoint operator commuting with an increasing family of projections we study the multifunction an open set of the topology containing , where is the spectrum of on . Let be the measure of maximal spectral type. We study the condition that is essentially a singleton, is not a singleton. We show that if is the density topology and if satisfies the density theorem, in particular if it is absolutely continuous with respect to the Lebesgue measure, then this condition is equivalent to the fact that is a Borel function of . If is the usual topology then the condition is equivalent to the fact that is approched in norm by step functions , where the set of intervals covers the set where is a singleton.
9.
Lorenzo Robbiano Moss Sweedler 《Proceedings of the American Mathematical Society》1998,126(8):2213-2219
For an ideal or -subalgebra of , consider subfields , where is generated - as ideal or -subalgebra - by polynomials in . It is a standard result for ideals that there is a smallest such . We give an algorithm to find it. We also prove that there is a smallest such for -subalgebras. The ideal results use reduced Gröbner bases. For the subalgebra results we develop and then use subduced SAGBI (bases), the analog to reduced Gröbner bases.
10.
11.
Rodrigo Bañ uelos Tom Carroll Elizabeth Housworth 《Proceedings of the American Mathematical Society》1998,126(2):577-585
Let be a convex planar domain of finite inradius . Fix the point and suppose the disk centered at and radius is contained in . Under these assumptions we prove that the symmetric decreasing rearrangement in of the Green's function , for fixed , is dominated by the corresponding quantity for the strip of width . From this, sharp integral mean inequalities for the Green's function and the conformal map from the disk to the domain follow. The proof is geometric, relying on comparison estimates for the hyperbolic metric of with that of the strip and a careful analysis of geodesics.
12.
13.
Victoria Paolantoni 《Proceedings of the American Mathematical Society》1998,126(6):1733-1738
Let be a smooth real hypersurface of and a compact submanifold of . We generalize a result of A. Boggess and R. Dwilewicz giving, under some geometric conditions on and , an estimate of the submeanvalue on of any function on a neighbourhood of , by the norm of on a neighbourhood of in .
14.
Dave Witte 《Proceedings of the American Mathematical Society》1998,126(4):1005-1015
Let and be matrices of determinant over a field , with or . We show that if is not a scalar matrix, then is a product of matrices similar to . Analogously, we conjecture that if and are elements of a semisimple algebraic group over a field of characteristic zero, and if there is no normal subgroup of containing but not , then is a product of conjugates of . The conjecture is verified for orthogonal groups and symplectic groups, and for all semisimple groups over local fields. Thus, in a connected, semisimple Lie group with finite center, the only conjugation-invariant subsemigroups are the normal subgroups.
15.
Tadashi Yanai 《Proceedings of the American Mathematical Society》1998,126(8):2221-2228
In this paper, we prove the following two results which generalize the theorem concerning automorphic-differential endomorphisms asserted by J. Bergen. Let be a ring, its left Martindale quotient ring and a right ideal of having no nonzero left annihilator. (1) Let be a pointed coalgebra which measures such that the group-like elements of act as automorphisms of . If is prime and for , then . Furthermore, if the action of extends to and if such that , then . (2) Let be an endomorphism of given as a sum of composition maps of left multiplications, right multiplications, automorphisms and skew-derivations. If is semiprime and , then .
16.
Chih-Nung Hsu 《Proceedings of the American Mathematical Society》1998,126(7):1955-1961
Let be a global function field, a degree one prime divisor of and let be the Dedekind domain of functions in regular outside . Let be the Hilbert class field of , the integral closure of in . Let be a rank one normalized Drinfeld -module and let be a prime ideal in . We explicitly determine the finite -module structure of . In particular, if , is an odd prime number and is the Carlitz -module, then the finite -module is always cyclic.
17.
Gabriel Navarro 《Proceedings of the American Mathematical Society》1998,126(1):65-66
Suppose that is a Sylow -subgroup of a finite -solvable group . If , then the number of -conjugates of in can be read off from the character table of .
18.
Massimiliano Mella 《Proceedings of the American Mathematical Society》1998,126(8):2199-2204
Let be an -dimensional variety and an ample vector bundle on of rank . We give a complete classification of pairs , with log terminal and such that is not ample. The results we obtain were conjectured by Fujita, and recently by Zhang.
19.
A. Skopenkov 《Proceedings of the American Mathematical Society》1998,126(8):2467-2476
For a space let . Let act on and on by exchanging factors and antipodes respectively. We present a new short proof of the following theorem by Weber: For an -polyhedron and , if there exists an equivariant map , then is embeddable in . We also prove this theorem for a peanian continuum and . We prove that the theorem is not true for the 3-adic solenoid and .
20.
B. P. Duggal 《Proceedings of the American Mathematical Society》1998,126(7):2047-2052
Given a Hilbert space , let be operators on . Anderson has proved that if is normal and , then for all operators . Using this inequality, Du Hong-Ke has recently shown that if (instead) , then for all operators . In this note we improve the Du Hong-Ke inequality to for all operators . Indeed, we prove the equivalence of Du Hong-Ke and Anderson inequalities, and show that the Du Hong-Ke inequality holds for unitarily invariant norms.