In mathematical logic, reduction to Skolem normal form (SNF) is a method for removing existential quantifiers from formal logic statements, often performed as the first step in an automated theorem prover. A formula of first-order logic is in Skolem normal form (named after Thoralf Skolem) if it is in prenex normal form with only universal first-order quantifiers. Every first-order formula can be converted into Skolem normal form while not changing its satisfiability via a process called Skolemization (sometimes spelled "Skolemnization"). The resulting formula is not necessarily equivale...

A doge (; plural dogi or doges) was an elected, chief-of-state lordship, the ruler of the republic in many of the Italian city-states during the medieval and renaissance periods, in the Italian "crowned republics". Etymology The word is from a Venetian word that descends from the Latin dux (as do the English duke and the standard Italian duce and duca), meaning "leader", especially in a military context. The wife of a doge is styled a dogaressa. Title The title of doge was used for the elected chief of state in a number of Italian "crowned republics". The two best known such republic...

The Public Broadcasting Service (PBS) is an American broadcast television network. The non-profit public broadcaster has 354 member television stations which hold collective ownership. The network's headquarters is located in Arlington, Virginia. PBS is the most prominent provider of television programs to public television stations in the United States, distributing series such as Sesame Street, PBS NewsHour, Masterpiece, Frontline and Antiques Roadshow. Since the mid-2000s, Roper polls commissioned by PBS have consistently placed the service as America's most-trusted national institut...