Theory of computationIn theoretical computer science and mathematics, the theory of computation is the branch that deals with what problems can be solved on a model of computation, using an algorithm, how efficiently they can be solved or to what degree (e.g., approximate solutions versus precise ones). The field is divided into three major branches: automata theory and formal languages, computability theory, and computational complexity theory, which are linked by the question: "What are the fundamental capabilities and limitations of computers?".
AshlarAshlar (ˈæʃlər) is finely dressed (cut, worked) stone, either an individual stone that has been worked until squared, or a structure built from such stones. Ashlar is the finest stone masonry unit, generally rectangular cuboid, mentioned by Vitruvius as opus isodomum, or less frequently trapezoidal. Precisely cut "on all faces adjacent to those of other stones", ashlar is capable of very thin joints between blocks, and the visible face of the stone may be quarry-faced or feature a variety of treatments: tooled, smoothly polished or rendered with another material for decorative effect.
Walls of ConstantinopleThe Walls of Constantinople (Τείχη της Κωνσταντινουπόλεως) are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul in Turkey) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built.
PlasterPlaster is a building material used for the protective or decorative coating of walls and ceilings and for moulding and casting decorative elements. In English, "plaster" usually means a material used for the interiors of buildings, while "render" commonly refers to external applications. The term stucco refers to plasterwork that is worked in some way to produce relief decoration, rather than flat surfaces. The most common types of plaster mainly contain either gypsum, lime, or cement, but all work in a similar way.
Dimension stoneDimension stone is natural stone or rock that has been selected and finished (e.g., trimmed, cut, drilled or ground) to specific sizes or shapes. Color, texture and pattern, and surface finish of the stone are also normal requirements. Another important selection criterion is durability: the time measure of the ability of dimension stone to endure and to maintain its essential and distinctive characteristics of strength, resistance to decay, and appearance.
Skilled workerA skilled worker is any worker who has special skill, training, knowledge which they can then apply to their work. A skilled worker may have learned their skills on the work experience, on-the-job training, an apprenticeship program or formal education. These skills often lead to better outcomes economically. The definition of a skilled worker has seen change throughout the 20th century, largely due to the industrial impact of the Great Depression and World War II.
TradespersonA tradesperson is a skilled worker that specializes in a particular trade. Tradespeople usually gain their skills through work experience, on-the-job training, an apprenticeship program or formal education. As opposed to a craftsperson or an artisan, a tradesperson is not necessarily restricted to manual work. In Victorian England: The terms "skilled worker," "craftsman," "artisan," and "tradesman" were used in senses that overlap. All describe people with specialized training in the skills needed for a particular kind of work.
