All articles starting with P

Position eigenstates and continuous bases

Position eigenstates are the generalized eigenvectors |x⟩ of the quantum-mechanical position operator, forming a continuous basis normalized with the Dirac delta and not normalizable within the Hilbert space.

Position encoding

Position encoding is the family of techniques a transformer uses to inject token order information, since self-attention alone treats input as an unordered set of vectors.

Position interpolation

Position interpolation is a 2023 technique from Meta for extending a language model's context window by linearly rescaling rotary position embeddings, extending LLaMA models to 32768 tokens.

Position operator

The position operator in quantum mechanics represents a particle's spatial location, acting as multiplication by the coordinate; its relativistic extension, the Newton–Wigner operator, is debated.

Position paper

A position paper is a document stating an arguable opinion on an issue, defended with evidence and counterargument responses; used by organizations for policy, in Model UN for country positions, and as academic argument writing.

Position representation

The position representation is the description of a quantum state by its wavefunction, obtained by projecting the state vector onto the eigenstates of the position operator.

Position vector

A position vector, also called a location vector or radius vector, points from a coordinate system's origin to a given point, representing its location as a directed displacement.

Position weight matrix

A position weight matrix (PWM), also called a position-specific scoring matrix (PSSM), is a bioinformatics model that represents sequence motifs as a table of per-position scores.

Position-based dynamics

Position-based dynamics (PBD) is a physically based simulation method introduced by Matthias Müller and colleagues in 2007, widely used for real-time cloth, hair, and fluids in games.

Position–momentum Fourier duality

Position–momentum Fourier duality is the fact that a quantum particle's position-space and momentum-space wave functions are Fourier transforms of each other, so both describe the same state.

Position–momentum uncertainty relation

The position–momentum uncertainty relation states that a quantum particle's position and momentum spreads obey Δx·Δp ≥ ℏ/2, proved by Kennard in 1927 and underlying atomic stability.

Positional cloning

Positional cloning is a genetics method for identifying a disease-causing gene from its chromosomal position alone, by linkage mapping followed by physical cloning of the interval.

Positional encoding

Positional encoding is a family of techniques that injects token order information into neural networks such as transformers, whose self-attention otherwise cannot distinguish sequence positions.

Positional isomerism

Positional isomerism, also called regioisomerism, is a form of constitutional isomerism in which compounds share the same molecular formula and carbon skeleton but differ in the position of a substituent or functional group.

Positional notation

Positional notation, also called place-value notation, is a way of writing numbers in which each digit's value depends on its position, as in decimal and binary.

Positioning (marketing)

Positioning in marketing is establishing a brand's place in target customers' minds relative to competitors, a concept developed by Al Ries and Jack Trout in the 1970s.

Positions (album)

Positions is Ariana Grande's sixth studio album, released October 30, 2020 on Republic Records; a lockdown-recorded, R&B-focused 14-track set with Doja Cat, The Weeknd, and Ty Dolla $ign that debuted at number one on the Billboard 200.

Oct 22, 2026

Positive Action

Positive Action was a campaign of strikes and boycotts against British rule in the Gold Coast, declared by Kwame Nkrumah's Convention People's Party in January 1950.

Positive airway pressure

Positive airway pressure (PAP), including CPAP, APAP, and BiPAP, delivers pressurized air through a mask to keep the upper airway open during sleep; first reported by Sullivan in 1981, it is the mainstay treatment for obstructive sleep apnea.

Positive and Negative Affect Schedule

The Positive and Negative Affect Schedule (PANAS) is a self-report questionnaire measuring positive and negative affect as separate dimensions, introduced by Watson, Clark, and Tellegen in 1988.

Positive and negative predictive values

Positive and negative predictive values (PPV and NPV), also called precision rate, are the probabilities that a test result correctly reflects whether a person has the condition tested for.

Positive and Negative Syndrome Scale

The Positive and Negative Syndrome Scale (PANSS) is a 30-item clinician-rated interview measuring schizophrenia symptom severity, widely used as a gold standard and a primary endpoint in drug trials.

Positive bias temperature instability

Positive bias temperature instability (PBTI) is a reliability phenomenon in n-channel MOSFETs in which positive gate bias at elevated temperature causes electron trapping that shifts the threshold voltage.

Sep 19, 2026

Positive Black Soul (group)

Positive Black Soul is a Senegalese hip hop duo formed in Dakar in 1989 by Didier Awadi and Duggy Tee, whose 1995 album Salaam opened African rap's history.

Positive Christianity

Positive Christianity (Positives Christentum), the Nazi-era religious formula from point 24 of the 1920 NSDAP programme, promoted by the German Christians' Reich Church project and opposed by the Confessing Church.

Positive control

A positive control is an experimental condition with a known, expected response, used to verify that an assay can detect that response; a failing control suggests a flaw.

Positive definite matrix

A positive definite matrix is a Hermitian or real symmetric matrix for which the quadratic form is positive for every nonzero vector, equivalently all its eigenvalues are positive.

Positive deviance

Positive deviance is a method that studies people who achieve unusually good outcomes under the same constraints as their peers, then spreads their uncommon practices.

Oct 10, 2026

Positive economics

Positive economics is the branch of economics that makes descriptive, testable statements about what is, a distinction drawn by John Neville Keynes in 1890 and central to Milton Friedman's 1953 methodology essay.