Th e paper analyses the possibilities to develop communist heritage tourism in Bulgaria. After a review of related literature, the paper identifi es fi ve characteristics of communist heritage tourism: ideologically overburdened type of tourism, controversial, represents a limited time period of history, represents a personality cult, concentration of resources in places related with communist ...

Introduction Parasites live in a host from which they obtain food and protection. They may harm but usually do not benefit the host. The word “parasite” is derived from the Latin and Greek languages meaning, in general, “one who eats at the table of another.” It is said that a “good” parasite does not overtly harm or kill its host. It is theoretically possible that a more benign parasite (e.g. ...

The odd composite n < 25 • 10 such that 2n_1 = 1 (mod n) have been determined and their distribution tabulated. We investigate the properties of three special types of pseudoprimes: Euler pseudoprimes, strong pseudoprimes, and Carmichael numbers. The theoretical upper bound and the heuristic lower bound due to Erdös for the counting function of the Carmichael numbers are both sharpened. Several...