All articles starting with E
17,681 articles
Entropy as an arrow of time
Entropy as an arrow of time is the thesis that time's direction is fixed by entropy increasing toward the future, grounded in the second law of thermodynamics.
Entropy balancing
Entropy balancing is a reweighting method for causal inference and survey statistics, introduced by Jens Hainmueller in 2012, that reweights controls to match treated-group covariate moments.
Entropy generation analysis
Entropy generation analysis is a second-law method quantifying irreversibilities and exergy destruction in thermal systems; its design form, entropy generation minimization, was introduced by Adrian Bejan in 1982.
Entropy of entanglement
The entropy of entanglement, or entanglement entropy, is a measure of quantum entanglement for a pure bipartite quantum state, defined as the von Neumann entropy of either subsystem's reduced density matrix.
Entropy of mixing
The entropy of mixing, also called Gibbs theorem, is the thermodynamic entropy change on combining pure substances; it is always positive for ideal mixtures and depends only on mole fractions.
Entropy of the universe
The entropy of the universe is the total thermodynamic entropy in the observable universe, estimated at about 10^104 k, with supermassive black holes contributing almost all of it.
Entropy production
Entropy production, also called entropy generation, is the rate at which entropy is created inside a system by irreversible processes, quantifying how far a process sits from thermodynamic equilibrium.
Entropy weight method
The entropy weight method is an objective weighting technique in multi-criteria decision analysis that derives criterion weights from Shannon entropy in the decision matrix, minimizing subjective judgment.
Entropy-stabilized PbTe
Entropy-stabilized PbTe is lead telluride thermoelectric material in which multi-element alloying raises configurational entropy, stabilizing a single-phase rock-salt solid solution and lowering lattice thermal conductivity.
Entropy-weighted TOPSIS
Entropy-weighted TOPSIS is a multi-criteria decision-making method that derives criterion weights objectively from Shannon entropy, then ranks alternatives by their closeness to ideal and anti-ideal solutions.
Entry into force of treaties
Entry into force of treaties is the moment a treaty becomes binding under international law, per Vienna Convention Article 24; the CTBT, adopted in 1996, has never entered into force.
Entry into the World Trade Organization
Entry into the World Trade Organization (加入世界贸易组织) was the People's Republic of China's accession to the WTO, completed on 11 December 2001 after a fifteen-year negotiation.
Entry of women to Sabarimala
The entry of women to Sabarimala temple concerns the custom barring women aged 10 to 50, which India's Supreme Court struck down in September 2018.
Entry Only
Entry Only (Sólo Entrada / Only Entrance) is a Mexico City place record, built from OpenStreetMap data, that lists a Chapultepec Zoo entrance gate as a free, customers-only family attraction and zoo, open daily 09:00-17:00.
Entscheidungsproblem
The Entscheidungsproblem, also known as Church's theorem, is the problem of deciding validity in first-order logic, posed by Hilbert and Ackermann in 1928 and proved unsolvable by Church and Turing in 1936.
ENTSO-E
ENTSO-E, the European Network of Transmission System Operators for Electricity, is the Brussels-based association of 40 electricity TSOs from 36 countries, created under EU law in 2009.
Entwicklung series
The Entwicklung series, also called Entwicklungserie or E-Serie, was a German program of 1943 to develop standardized, mass-producible tanks and tank destroyers replacing the Panther and Tiger.
Enucleation of the eye
Enucleation of the eye is surgical removal of the entire globe, unlike evisceration (contents only) or exenteration (whole orbit). First documented by Bartisch in 1583; used for intraocular malignancy, blind painful eye, and trauma, usually with an orbital implant and later prosthesis.
Enugu
Enugu, the Coal City, capital of Enugu State in southeastern Nigeria, founded in 1909 after coal was discovered at Udi hill; long-serving regional capital, Igbo cultural hub, about 1.1 million residents.
Enugu Air
Enugu Air is a commercial airline owned by the Enugu State Government of Nigeria, inaugurated in July 2025 as the country's second state-owned commercial airline after Ibom Air.
Enugu State
Enugu State is a state in southeastern Nigeria created in 1991 out of the old Anambra State, with its capital at Enugu, the historic Coal City.
Enuka Okuma
Enuka Okuma (born 1976, Vancouver) is a Canadian actress, writer, and producer known as Traci Nash in all 74 episodes of Rookie Blue, Sloane Mitchell in Workin' Moms, and currently Teri Rogers-Collins in Hulu's Paradise.
Enūma Anu Enlil
Enūma Anu Enlil, also written Enuma Anu Ellil, is the canonical Babylonian omen series for celestial divination, compiled in its present form around 1000 BC.
Enūma Eliš
Enūma Eliš, also called Enuma Elish, is a Babylonian Akkadian creation poem on seven tablets, probably composed in the twelfth century BC, celebrating the god Marduk.
Enumclaw horse sex case
Enumclaw horse sex case, also called the Mr. Hands incident: July 2, 2005 death of Kenneth Pinyan from sex with a stallion near Enumclaw, Washington; led to Washington's 2006 bestiality law, a Class C felony.
Enumerated type
An enumerated type, also called an enum, is a data type restricted to a named, fixed set of constants like compass directions, introduced in Pascal in 1970.
Enumeration
Enumeration is the branch of combinatorics concerned with counting the elements of finite sets, using tools such as generating functions, bijective proofs, and Pólya's theorem for counting under symmetry.
Enumeration algorithm
An enumeration algorithm lists every element of a finite solution set exactly once, without repetition, producing results as a stream that can be consumed as they appear.
Enumeration degree
An enumeration degree is an equivalence class of sets of natural numbers under enumeration reducibility, where one set is computed from positive information about another.
Enumerative combinatorics
Enumerative combinatorics is the branch of mathematics that counts the elements of finite sets, seeking exact formulas, recurrences, or asymptotics for counting functions, as in Cayley's tree formula.