โ*(๐ฆ) and other lattices of recursively enumerable sets
Richard A. Shore ยท Proceedings of the American Mathematical Society ยท 1980
We study the direct product operation on lattices which are principal filters of E โ {\mathcal {E}^ \ast } , the lattice of r.e. sets modulo finite sets, to generate new isomorphism types of such filters and to characterize the one generated by the complete r.e. set K .