Our purpose is to formalize two potential refinements of single-sorted algebraic data types – subalgebras and algebras which satisfy equivalence relations – by considering their categorical interpretation. We review the usual categorical formalization of singleand multi-sorted algebraic data types as initial algebras, and the correspondence between algebraic data types and endofunctors. We intr...

Inspired by Cardelli’s pioneering work, many type disciplines for object-oriented programming are based on enrichments of structural type theories with constructs such as subtyping and bounded polymorphism. A principal benefit of such a formulation is that the absence of “message not understood” errors is an immediate corollary of the type safety theorem. A principal drawback is that the result...

In this paper we present a calculus for re nement of business process models based on a precise de nition of business processes and process nets Business process models are a vital concept for communicating with experts of the application domain Depending on the roles and responsibilities of the application domain experts involved process models are discussed on di erent levels of ab straction ...

Oxygen, metals, silicon, and glass are raw materials that will be required for long-term habitation and production of structural materials and solar arrays on the Moon. A process sequence is proposed for refining these materials from lunar regolith, consisting of separating the required materials from lunar rock with fluorine. The fluorine is brought to the Moon in the form of potassium fluorid...

3. A lower bound To obtain a lower bound we count only those sequences of refinements which include the partition 1 .2.3 . . . d . r of n into d or d + 1 parts, d of which are of different size, where 0 < r = n-$d(d + 1) < d, so that J(2n) > d > J(2n)-3. Moreover we only count sequences in which we split off 1 from each of the d 1 parts of different size greater than 1. These d 1 steps can be m...

Unlike word processing, the changes involved in using rn have not concerned the program, but have instead involved the type of user, equipment, and environment, all of which have evolved through the years and into the 90s. This paper profiles the various changes and offers suggestions for future structure and encouragement in the use of lQX.

We use a K-theory recipe of Thomason to obtain classi cations of triangulated subcategories via re ning some standard thick subcategory theorems. We apply this recipe to the full subcategories of nite objects in the derived categories of rings and the stable homotopy category of spectra. This gives, in the derived categories, a complete classi cation of the triangulated subcategories of perfect...

A well-written research article is quintessential for the innovative work to be appreciated and receiving a good number of citations. But writing a good research article is not an art. With due care and understanding the focus requirements can help a researcher to present his work with high scientific impact. The seeds of a research article are in the primary research or discovery by a research...

This article explores coordinated scheduling problem arising in steelmaking and multi-refining operations. Jobs are first processed in converters and then transported downstream to be processed in refining furnaces in which two different transporters are employed in tandem at the stage of transportation. There exist multi-refining jobs. The objective is to minimize the maximum completion time s...