8,934 research outputs found
Rings Over Which Cyclics are Direct Sums of Projective and CS or Noetherian
R is called a right WV -ring if each simple right R-module is injective
relative to proper cyclics. If R is a right WV -ring, then R is right uniform
or a right V -ring. It is shown that for a right WV-ring R, R is right
noetherian if and only if each right cyclic module is a direct sum of a
projective module and a CS or noetherian module. For a finitely generated
module M with projective socle over a V -ring R such that every subfactor of M
is a direct sum of a projective module and a CS or noetherian module, we show M
= X \oplus T, where X is semisimple and T is noetherian with zero socle. In the
case that M = R, we get R = S \oplus T, where S is a semisimple artinian ring,
and T is a direct sum of right noetherian simple rings with zero socle. In
addition, if R is a von Neumann regular ring, then it is semisimple artinian.Comment: A Para\^itre Glasgow Mathematical Journa
The BTC40 Survey for Quasars at 4.8 < z < 6
The BTC40 Survey for high-redshift quasars is a multicolor search using
images obtained with the Big Throughput Camera (BTC) on the CTIO 4-m telescope
in V, I, and z filters to search for quasars at redshifts of 4.8 < z < 6. The
survey covers 40 sq. deg. in B, V, & I and 36 sq. deg. in z. Limiting
magnitudes (3 sigma) reach to V = 24.6, I = 22.9 and z = 22.9. We used the
(V-I) vs. (I-z) two-color diagram to select high-redshift quasar candidates
from the objects classified as point sources in the imaging data. Follow-up
spectroscopy with the AAT and CTIO 4-m telescopes of candidates having I < 21.5
has yielded two quasars with redshifts of z = 4.6 and z = 4.8 as well as four
emission line galaxies with z = 0.6. Fainter candidates have been identified
down to I = 22 for future spectroscopy on 8-m class telescopes.Comment: 27 pages, 8 figures; Accepted for publication in the Astronomical
Journa
Some rings for which the cosingular submodule of every module is a direct summand
The submodule Z(M) = ∩{N | M/N is small in its injective hull} was introduced by Talebi and Vanaja
in 2002. A ring R is said to have property (P ) if Z(M) is a direct summand of M for every R-module M . It is
shown that a commutative perfect ring R has (P ) if and only if R is semisimple. An example is given to show that
this characterization is not true for noncommutative rings. We prove that if R is a commutative ring such that the class
{M ∈ Mod−R | ZR(M) = 0} is closed under factor modules, then R has (P ) if and only if the ring R is von Neumann
regular
Recent Decisions
Comments on recent decisions by William C. Rindone, Ray F. Drexler, Eugene G. Griffin, Ronald Patrick Smith, and John G. Curran
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