The singular submodule splits off

Submodule Algebras

The complement operation on modules has not been argued so far as we know. We observe that it plays an important role in software maintenance, as well as join and meet operations. A de nition of a module and operations on them is given in category theoretic terms; we adopt well-known characterization of complement as a left adjoint to join. The de nition is rst given locally and then extended t...

Submodule Construction Using Derivatives

Top-down design methodology is one of the widely used approaches to the design of complex concurrent systems. In this approach, the speciication of a system is decomposed into a set of submodules whose concurrent behavior is equivalent to that of the system speciication. The following problem is of particular importance when using this methodology: given the speciication of a system and some of...

Killer splits

Although killer whales showed overall low levels of mitochondrial sequence variation, the researchers found three fixed differences between the open-sea type A whales compared with the two ice-inhabiting, other forms. " The genetic pattern suggests that, for females at least, there is no gene flow between them, " the authors write. But they do point out that the evidence for reproductive isolat...

Animal splits

of protein for the mountain pygmy possum, a tiny 45 g possum and the only mammal unique to alpine and subalpine areas of Australia. Pygmy possums have a range totalling less than ten square kilometres and almost entirely coincident with Australian ski resorts, so it is perhaps fortuitous for them that they hibernate during the winter. Winter-active mammals, like the dusky antechinus (a carnivor...

Matroids from hypersimplex splits