Decision problemIn computability theory and computational complexity theory, a decision problem is a computational problem that can be posed as a yes–no question of the input values. An example of a decision problem is deciding by means of an algorithm whether a given natural number is prime. Another is the problem "given two numbers x and y, does x evenly divide y?". The answer is either 'yes' or 'no' depending upon the values of x and y. A method for solving a decision problem, given in the form of an algorithm, is called a decision procedure for that problem.
Computational problemIn theoretical computer science, a computational problem is a problem that may be solved by an algorithm. For example, the problem of factoring "Given a positive integer n, find a nontrivial prime factor of n." is a computational problem. A computational problem can be viewed as a set of instances or cases together with a, possibly empty, set of solutions for every instance/case. For example, in the factoring problem, the instances are the integers n, and solutions are prime numbers p that are the nontrivial prime factors of n.
P versus NP problemThe P versus NP problem is a major unsolved problem in theoretical computer science. In informal terms, it asks whether every problem whose solution can be quickly verified can also be quickly solved. The informal term quickly, used above, means the existence of an algorithm solving the task that runs in polynomial time, such that the time to complete the task varies as a polynomial function on the size of the input to the algorithm (as opposed to, say, exponential time).
Travelling salesman problemThe travelling salesman problem (TSP) asks the following question: "Given a list of cities and the distances between each pair of cities, what is the shortest possible route that visits each city exactly once and returns to the origin city?" It is an NP-hard problem in combinatorial optimization, important in theoretical computer science and operations research. The travelling purchaser problem and the vehicle routing problem are both generalizations of TSP.
Free FranceFree France (France Libre) was a political entity that claimed to be the legitimate government of France following the dissolution of the Third Republic. Led by French general Charles de Gaulle, Free France was established as a government-in-exile in London in June 1940 after the Fall of France during World War II and fought the Axis as an Allied nation with its Free French Forces (Forces françaises libres). Free France also supported the resistance in Nazi-occupied France, known as the French Forces of the Interior, and gained strategic footholds in several French colonies in Africa.
French ResistanceThe French Resistance (La Résistance) was a collection of organizations that fought the Nazi occupation of France and the collaborationist Vichy régime in France during the Second World War. Resistance cells were small groups of armed men and women (called the Maquis in rural areas) who conducted guerrilla warfare and published underground newspapers. They also provided first-hand intelligence information, and escape networks that helped Allied soldiers and airmen trapped behind Axis enemy lines.
French Foreign LegionThe French Foreign Legion (Légion étrangère) is a corps of the French Army that consists of several specialties: infantry, cavalry, engineers, airborne troops. It was created in 1831 to allow foreign nationals into the French Army. It formed part of the Armée d’Afrique, the French Army's units associated with France's colonial project in Africa, until the end of the Algerian war in 1962. Legionnaires are highly trained soldiers and the Legion is unique in that it is open to foreign recruits willing to serve in the French Armed Forces.
