The tensor product of functors; satellites; and derived functors

Isocategories and Tensor Functors

In this paper, I show how the concepts of an isocategory (category all of whose morphisms are isomorphisms) and the corresponding concept of an isofunctor can be used to improve the conceptural infrastructure of many branches of mathematics. The crucial new idea is that of a natural assignment, a modification of the idea of a natural tansformation introduced by Eilenberg and Mac Lane. Isofuncto...

On the Object-wise Tensor Product of Functors to Modules

We investigate preserving of projectivity and injectivity by the object-wise tensor product of RC-modules, where C is a small category. In particular, let O(G,X) be the category of canonical orbits of a discrete group G, over a G-set X. We show that projectivity of RO(G,X)-modules is preserved by this tensor product. Moreover, if G is a finite group, X a finite G-set and R is an integral domain...

Derived Functors

Non-additive Functors, Their Derived Functors, and the Suspension Homomorphism.

3E. L. Post, J. Symb. Logic, 12, 1-11, 1947. 4In the sense of Post, the word problem for Z is reducible to that for sp (2:). 5 W. Magnus, Math. Annalen, 106, 295-307, 1932. 6 DanaScott, abstract, J. Symb. Logic, 21, 111-112, 1956. 7Marshall Hall, J. Symb. Logic, 14, 115-118, 1949. 8 G. Higman, B. H. Neumann, and H. Neumann, J. London Math. Soc., 24, 247-254, 1949. 9 As defined, UG, Part I, p. 2...

Composite Cotriples and Derived Functors

The main result of [Barr (1967)] is that the cohomology of an algebra with respect to the free associate algebra cotriple can be described by the resolution given by U. Shukla in [Shukla (1961)]. That looks like a composite resolution; first an algebra is resolved by means of free modules (over the ground ring) and then this resolution is given the structure of a DG-algebra and resolved by the ...