PCP

PCP may refer to:

Computing

Medicine and pharmaceutics

Politics

Probabilistically checkable proof

In computational complexity theory, a probabilistically checkable proof (PCP) is a type of proof that can be checked by a randomized algorithm using a bounded amount of randomness and reading a bounded number of bits of the proof. The algorithm is then required to accept correct proofs and reject incorrect proofs with very high probability. A standard proof (or certificate), as used in the verifier-based definition of the complexity class NP, also satisfies these requirements, since the checking procedure deterministically reads the whole proof, always accepts correct proofs and rejects incorrect proofs. However, what makes them interesting is the existence of probabilistically checkable proofs that can be checked by reading only a few bits of the proof using randomness in an essential way.

Probabilistically checkable proofs give rise to many complexity classes depending on the number of queries required and the amount of randomness used. The class PCP[r(n),q(n)] refers to the set of decision problems that have probabilistically checkable proofs that can be verified in polynomial time using at most r(n) random bits and by reading at most q(n) bits of the proof. Unless specified otherwise, correct proofs should always be accepted, and incorrect proofs should be rejected with probability greater than 1/2. The PCP theorem, a major result in computational complexity theory, states that PCP[O(log n),O(1)] = NP.

Peruvian Communist Party

The Peruvian Communist Party (in Spanish: Partido Comunista Peruano) is a communist party in Peru. It was founded in 1928 by José Carlos Mariátegui, under the name Partido Socialista del Perú (Socialist Party of Peru). In 1930 the name was changed to PCP. PCP is often identified as PCP [Unidad], to separate it from the Communist Party of Peru.

Jorge Del Prado was the general secretary between 1966 and 1991. In 1980 the PCP and other left-wing groups formed the United Left.

The main political base of the PCP is currently located at Plaza Ramón Castilla, Lima and is led by Roberto De La Cruz Huama. PCP publishes Unidad (Unity) and Nuestra Bandera (Our Flag).

In the 2011 general election the party took part in the successful Peru Wins alliance of Ollanta Humala.

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Pitch (baseball)

In baseball, a pitch is the act of throwing a baseball toward home plate to start a play. The term comes from the Knickerbocker Rules. Originally, the ball had to be literally "pitched" underhand, as with pitching horseshoes. Overhand throwing was not allowed until 1884.

The biomechanics of pitching have been studied extensively. The phases of throwing include windup, early cocking, late cocking, early acceleration, late acceleration, deceleration, and follow-through.

Pitchers throw a variety of pitches, each of which has a slightly different velocity, trajectory, movement, hand position, wrist position and/or arm angle. These variations are introduced to confuse the batter in various ways, and ultimately aid the defensive team in getting the batter or baserunners out. To obtain variety, and therefore enhance defensive baseball strategy, the pitcher manipulates the grip on the ball at the point of release. Variations in the grip cause the seams to "catch" the air differently, thereby changing the trajectory of the ball, making it harder for the batter to hit.

Flight dynamics

Flight dynamics is the study of the performance, stability, and control of vehicles flying through the air or in outer space. It is concerned with how forces acting on the vehicle influence its speed and attitude with respect to time.

In fixed-wing aircraft, the changing orientation of the vehicle with respect to the local air flow is represented by two critical parameters, angle of attack ("alpha") and angle of sideslip ("beta"). These angles describe the vector direction of airspeed, important because it is the principal source of modulations in the aerodynamic forces and moments applied to the aircraft.

Spacecraft flight dynamics involve three forces: propulsive (rocket engine), gravitational, and lift and drag (when traveling through the earths or any other celestial atmosphere). Because aerodynamic forces involved with spacecraft flight are very small, this leaves gravity as the dominant force.

Aircraft and spacecraft share a critical interest in their orientation with respect to the earth horizon and heading, and this is represented by another set of angles, "yaw," "pitch" and "roll" which angles match their colloquial meaning, but also have formal definition as an Euler sequence. These angles are the product of the rotational equations of motion, where orientation responds to torque, just as the velocity of a vehicle responds to forces. For all flight vehicles, these two sets of dynamics, rotational and translational, operate simultaneously and in a coupled fashion to evolve the vehicle's state (orientation and velocity) trajectory.

Pitch (filmmaking)

A pitch is a concise verbal (and sometimes visual) presentation of an idea for a film or TV series generally made by a screenwriter or film director to a film producer or studio executive in the hope of attracting development finance to pay for the writing of a screenplay.

"Pitch" is a contraction of the phrase "sales pitch". A pitch is used throughout different stages of production, such as casting and distribution, as well as to urge film producers to further fund a project. Filmmakers who devise a pitch tend to manufacture a production package, which is handed out to each potential investor during the pitch. The package contains the basic information for the filmmaker's project, such as a plot synopsis and budgeting values. Sometimes, filmmakers will produce an independent pitch trailer as a part of the package to help potential financiers better visualize the project and the filmmaker's vision.

Though pitches are usually made on the basis of a full script or teleplay, animated productions for both film and television are often pitched on the basis of storyboards alone. For example, the animated television show Phineas and Ferb was pitched from a storyboard. Co-founders of the project, Dan Povenmire and Jeff "Swampy" Marsh, needed to convince overseas executives for The Walt Disney Company to greenlight the series, so they drew a storyboard and recorded it as a reel. They then mixed it and dubbed it over with sound effects, voices, and narrative, then sent the recording to the executives, who accepted it.