Conducive integral domains

AbstractThis article introduces the concept of a conducive domain, that is, an integral domain each of whose overrings, apart from the quotient field, has nonzero conductor. The principal examples of conducive domains are all D + M constructions and all (pseudo-) valuation domains. Several characterizations are obtained, notably that a domain R is conducive if and only if R has a valuation overring with nonzero conductor. It is proved that if R is a conducive domain but not a field, then Spec(R) is pinched at a prime P such that the set of primes within P is linearly ordered. The converse is shown for R a Prüfer domain, in which case P = PRp. Consequences include pullback characterizations of the seminormal (resp., Prüfer) conducive domains. Special attention is paid to the class of conducive G-domains, with attendant interplay between “conducive” and the property of having a maximum overring

On the prime ideal structure of tensor products of algebras

AbstractThis paper is concerned with the prime spectrum of a tensor product of algebras over a field. It seeks necessary and sufficient conditions for such a tensor product to have the S-property, strong S-property, and catenarity. Its main results lead to new examples of stably strong S-rings and universally catenarian rings. The work begins by investigating the minimal prime ideal structure. Throughout, several results on polynomial rings are recovered, and numerous examples are provided to illustrate the scope and sharpness of the results

A note on strong locally divided domains

A uniform proof is given for the following fice assertions. Let R be an integral domain such each overring of R is a pseudovaluation domain (resp., divided domain; resp., going-down domain; resp., locally pseudovaluation domain; resp., locally divided domai). Then R/P has the same property, for each prime ideal P of R. The assertion for pseudovaluation domains was proved recently by Okabe-Yoshida by other methods

Autonomous rendezvous and docking: A commercial approach to on-orbit technology validation

The Space Automation and Robotics Center (SpARC), a NASA-sponsored Center for the Commercial Development of Space (CCDS), in conjunction with its corporate affiliates, is planning an on-orbit validation of autonomous rendezvous and docking (ARD) technology. The emphasis in this program is to utilize existing technology and commercially available components whenever possible. The primary subsystems that will be validated by this demonstration include GPS receivers for navigation, a video-based sensor for proximity operations, a fluid connector mechanism to demonstrate fluid resupply capability, and a compliant, single-point docking mechanism. The focus for this initial experiment will be expendable launch vehicle (ELV) based and will make use of two residual Commercial Experiment Transporter (COMET) service modules. The first COMET spacecraft will be launched in late 1992 and will serve as the target vehicle. The ARD demonstration will take place in late 1994, after the second COMET spacecraft has been launched. The service module from the second COMET will serve as the chase vehicle