All articles starting with P

Partial differential sign

∂, called the partial differential sign or "curly d", is the mathematical symbol for partial derivatives, which differentiate one variable while the others are held constant.

Partial discharge

Partial discharge is a localized electrical breakdown bridging only part of the insulation between two conductors; repeated events erode insulation and can end in complete failure.

Partial discharge detection is a diagnostic method in electrical engineering that identifies and measures localized insulation breakdowns in high-voltage equipment, governed by standards such as IEC 60270.

Partial discharge measurement

Partial discharge measurement is a high-voltage testing technique for detecting and measuring partial discharges in electrical insulation, using electrical, acoustic, or UHF methods governed by IEC 60270 and IEC TS 62478.

Oct 21, 2026

Partial dissociative identity disorder

Partial dissociative identity disorder (ICD-11 6B65) is a dissociative disorder with multiple personality states in which non-dominant states intrude on a dominant state without recurrently taking executive control; introduced in ICD-11, absent from DSM-5.

Partial evaluation

Partial evaluation is a program-specialization technique that turns a general program plus part of its input into a specialized residual program that runs faster on the remaining input.

Partial fraction decomposition

Partial fraction decomposition, or partial fraction expansion, rewrites a rational function as a polynomial plus simpler fractions, the standard first step for integrating rational functions.

Partial function

A partial function from X to Y assigns at most one value to each element of X but need not be defined everywhere; total functions are the special case.

Partial hepatectomy

A partial hepatectomy is an operation removing part of the liver while leaving enough healthy remnant tissue for function, used mainly for liver tumors and metastases.

Partial hydration

Partial hydration is a web rendering strategy in which a server emits complete HTML and the client adds JavaScript only to explicitly marked interactive regions, leaving static regions untouched.

Partial hysterectomy

Partial hysterectomy, also called subtotal or supracervical hysterectomy, is a gynecological operation that removes the body and fundus of the uterus while leaving the cervix in place.

Partial information decomposition

Partial information decomposition is an information theory framework that splits what multiple sources reveal about a target into redundant, unique, and synergistic components, introduced by Williams and Beer in 2010.

Partial laryngectomy

Partial laryngectomy is an operation for laryngeal cancer that removes the tumor-bearing part of the larynx while preserving voice, breathing, and swallowing, with five-year survival often exceeding 70%.

Partial least squares discriminant analysis

Partial least squares discriminant analysis (PLS-DA) is a supervised classification method that runs PLS regression against dummy-coded class labels, widely used in metabolomics and spectroscopy but prone to overfitting.

Partial least squares path modeling

Partial least squares path modeling (PLS-SEM, also called PLS-PM) is a variance-based structural equation modeling method estimating latent variables as weighted composites, suited to small samples.

Partial least squares regression

Partial least squares regression (PLS) projects many correlated predictors onto a few latent components and regresses on them; proposed by Herman Wold in the 1960s.

Partial meltdowns at Leningrad and Chernobyl

Partial meltdowns at Leningrad and Chernobyl were two early RBMK reactor accidents, at Leningrad Unit 1 in 1975 and Chernobyl Unit 1 in 1982, that foreshadowed the 1986 disaster.

Partial melting

Partial melting, also called anatexis, is the transformation of part of a solid rock into liquid magma, caused by decompression, heat input, or added water rather than complete melting.

Partial meniscectomy

Partial meniscectomy is an arthroscopic knee surgery that removes only the damaged portion of a torn meniscus, performed over 500,000 times a year in the United States.

Partial nephrectomy

Partial nephrectomy is a kidney cancer operation that removes the tumor with a thin rim of healthy tissue while leaving the rest of the kidney in place.

Oct 21, 2026

Partial nodular transformation of liver

Partial nodular transformation of liver (PNT) is a rare benign liver condition in which large regenerating nodules form at the hepatic hilus, often causing portal hypertension.

Partial Nuclear Test Ban Treaty

Partial Nuclear Test Ban Treaty (PTBT), 1963 treaty banning nuclear tests in the atmosphere, outer space, and underwater; signed by the US, UK, and USSR in Moscow, entered into force 10 October 1963.

Partial order reduction

Partial order reduction is a model checking technique that combats state explosion in concurrent systems by exploiting independence between transitions, preserving properties like LTL without the next operator.

Partial oxidation

Partial oxidation is an exothermic reforming process in which a hydrocarbon fuel reacts with limited oxygen, producing synthesis gas, a mixture of hydrogen and carbon monoxide.

Partial pressure

Partial pressure is the pressure a gas in a mixture would exert if it alone occupied the whole volume at the same temperature, summed per Dalton's law.

Partial pulpotomy

Partial pulpotomy is a vital pulp therapy in which a small portion of inflamed coronal pulp is removed and a bioceramic dressing is placed to preserve pulp vitality.

Partial redundancy elimination

Partial redundancy elimination (PRE) is a compiler optimization that removes computations redundant on some, but not all, execution paths, subsuming common subexpression elimination and loop-invariant code motion.

Partial response maximum likelihood

Partial response maximum likelihood (PRML) is a signal detection method for storage and communication channels that decodes controlled intersymbol interference using a Viterbi detector.

Oct 21, 2026

Partial septate uterus

Partial septate uterus: congenital uterine malformation with a fundal septum not reaching the internal cervical os; also called subseptate uterus; causes miscarriage risk, diagnosed by 3D ultrasound, treated by hysteroscopic resection.