We say that things happen accidentally when they do indeed happen, but only by chance. In the opposite situation, an essential happening is inescapable, its inevitability being the sine qua non for its very occurrence. This paper will investigate modal logics on a language tailored to talk about essential and accidental statements. Completeness of some among the weakest and the strongest such s...

Strategic programming is generic programming with the use of strategies. A strategy is a generic data-processing action which can traverse into heterogeneous data structures while mixing uniform and type-specific behaviour. With strategic programming, one gains full control over the application of basic actions, most notably full traversal control. Using a combinator style, traversal schemes ca...

Coin lemmas are one of the tools for the analysis of randomized distributed algorithms. Their principal role is to reduce the analysis of a randomized system to the analysis of an ordinary nondeterministic system. This paper describes the main ideas behind the formulation and use of coin lemmas and gives examples of coin lemmas of increasing complexity and generality.

For the past century, the total synthesis of natural products has served as the flagship of chemical synthesis and the principal driving force for discovering new chemical reactivity, evaluating physical organic theories, testing the power of existing synthetic methods, and enabling biology and medicine. This perspective article seeks to examine this time-honored and highly demanding art, disti...

In the literature, essence is formalized in two different ways, either de dicto, or de re. Following [11], we adopt its de dicto formalization: a formula is essential, if once it is true, it is necessarily true; otherwise, it is accidental. In this article, we study the model theory and axiomatization of the logic of essence and accident, i.e. the logic with essence operator (or accident operat...

For object-oriented programming, the Visitor pattern enables the deenition of a new operation on an object structure without changing the classes of the objects. The price has been that the set of classes must be xed in advance, and they must each have a so-called accept method. In this paper we demonstrate how to program visitors without relying on accept methods and without knowing all classe...

In this paper, we present a new transformation algorithm called distillationwhich can automatically transform higher-order functional programs into equivalent tail-recursive programs. Using this algorithm, it is possible to produce superlinear improvement in the runtime of programs. This represents a significant advance over the supercompilation algorithm, which can only produce a linear improv...

The traditional explanation of ATP coupling is based on the raising of the equilibrium constants of the biochemical reactions. But in the frames of the detailed balance, no coupling occurs under thermodynamic equilibrium. The role of ATP in coupling is not that it provides an increase in the equilibrium constants of thermodynamically unfavorable reactions but that the unfavorable reactions are ...

Objective: Establish an explanatory model through latent variables analysis of tobacco consumption based on al- cohol and alcohol attitudes towards in a sample university students Ecuador. Method: Descriptive correlational design using SEM (Structural Equation Mo- deling) techniques. Participants: 546 (69.2% women) aged between 17 41 years old (M= 21.3 old; SD= 2.6), from four universities (45....