THE retirement of a senior surgeon from the staff of a hospital in which he has worked for many years is often an impressive occasion. How much more so when the surgeon is actually the founder of the hospital to which he has given the best years ofhis life! So it was one hundred years ago with Frederick Salmon, the Founder of St. Mark's Hospital, who retired from the active staff in the year 18...

Control of elections refers to attempts by an agent to, via such actions as addition/deletion/partition of candidates or voters, ensure that a given candidate wins [BTT92]. An election system in which such an agent’s computational task is NP-hard is said to be resistant to the given type of control. The only election systems known to be resistant to all the standard control types are highly art...

Control and bribery are settings in which an external agent seeks to influence the outcome of an election. Constructive control of elections refers to attempts by an agent to, via such actions as addition/deletion/partition of candidates or voters, ensure that a given candidate wins [BTT92]. Destructive control refers to attempts by an agent to, via the same actions, preclude a given candidate’...

This article traces the development of possible worlds semantics through the work of: Wittgenstein, 1913–1921; Feys, 1924; McKinsey, 1945; Carnap, 1945–1947; McKinsey, Tarski and Jónsson, 1947–1952; von Wright, 1951; Becker, 1952; Prior, 1953– 1954; Montague, 1955; Meredith and Prior, 1956; Geach, 1960; Smiley, 1955–1957; Kanger, 1957; Hintikka, 1957; Guillaume, 1958; Binkley, 1958; Bayart, 195...

Given a tournament T = (X, A), we consider two tournament solutions applied to T: Slater’s solution and Copeland’s solution. Slater’s solution consists in determining the linear orders obtained by reversing a minimum number of directed edges of T in order to make T transitive. Copeland’s solution applied to T ranks the vertices of T according to their decreasing out-degrees. The aim of this pap...

In the Shift-Bribery problem we are given an election, a preferred candidate, and costs of shifting this candidate up voters' preference orders. The goal is to find such set shifts that ensures wins election. We give first polynomial-time approximation scheme for case positional scoring rules, Copeland rule show strong inapproximability results.