Physical world and mathematics

Lactitol

Lactitol, sold as the laxative Pizensy, is a sugar alcohol produced from lactose, used as a reduced-calorie bulk sweetener (E 966) and as an osmotic laxative for chronic idiopathic constipation.

A lactone is a cyclic ester of a hydroxy carboxylic acid, formed by intramolecular condensation with loss of water, occurring widely as flavor compounds, pheromones, and macrolide antibiotic pharmacophores.

Lactose

Lactose, also called milk sugar, is a disaccharide of glucose and galactose that occurs in mammalian milk, about 5% in cow's milk and 7% in human milk.

Ladder graph

The ladder graph Lₙ is the Cartesian product of two path graphs, P₂ and Pₙ, forming two rails joined by n rungs like a ladder.

Ladder operator

A ladder operator, also called a raising and lowering operator, is a quantum-mechanics operator that shifts an eigenstate's eigenvalue by a fixed step, solving spectra by algebra alone.

Ladder paradox

The ladder paradox, also called the barn-pole paradox, is a relativity thought experiment where a ladder seems to fit a barn in one frame but not another, resolved by the relativity of simultaneity.

Oct 10, 2026

Ladislaus Laszlo Marton

Ladislaus Laszlo Marton (1901–1979) was a Hungarian-born physicist who built one of the first electron microscopes in Brussels and recorded the first biological electron microscope images in 1934.

Oct 10, 2026

Ladislaus Marton

Ladislaus Marton (1901–1979 or 1980) was a Hungarian-born physicist who took the first electron micrographs of biological material and warned in 1934 that electron beams destroy cells.

Lady Day

Lady Day is the traditional English name for the Feast of the Annunciation, kept on 25 March and the first of the four English quarter days.

Lag BaOmer (ל״ג בעומר)

Lag BaOmer (ל״ג בעומר), also spelled Lag B'Omer, is a minor Jewish holiday on the 33rd day of the Omer, celebrated with bonfires and weddings.

LAGEOS

LAGEOS, short for Laser Geodynamics Satellite, is the name of two passive laser-ranging satellites launched by NASA in 1976 and 1992, used to define Earth's reference frame and test frame dragging.

Lagrange invariant

The Lagrange invariant, also called the optical invariant, is a quantity in paraxial geometrical optics that keeps the same value at every surface of an optical system.

Lagrange multipliers

Lagrange multipliers are auxiliary variables used to find the extrema of a function subject to equality constraints, introduced by Joseph-Louis Lagrange in the late 18th century.

Lagrange point

A Lagrange point is one of five positions where a small object can hold a fixed position relative to two large orbiting bodies, such as the Sun and Earth.

Lagrange points

Lagrange points are five positions near two orbiting bodies, such as the Sun and Earth, where a small object can hold a fixed position; spacecraft use them as parking spots.

Lagrange polynomial

A Lagrange polynomial, also called Lagrange interpolation or the Lagrange form, is a basis polynomial used in numerical analysis to build the unique polynomial through n+1 data points.

Lagrange's four-square theorem

Lagrange's four-square theorem, also known as Bachet's conjecture, states that every positive integer is a sum of at most four squares of integers, first proved by Lagrange in 1770.

Lagrange's theorem (group theory)

Lagrange's theorem, also called Lagrange's Group Theorem, is a result in group theory stating that the order of any subgroup of a finite group divides the order of the group.

Lagrangian (field theory)

The Lagrangian density, often just called the Lagrangian, is a function of a theory's fields and their spacetime derivatives whose integral over spacetime, the action, determines the field equations.

Lagrangian mechanics

Lagrangian mechanics, or Lagrangian dynamics, is a reformulation of classical mechanics in which equations of motion follow from the Lagrangian and Hamilton's principle of stationary action.

Lagrangian model (fluid dynamics)

A Lagrangian model describes a fluid by following individual parcels along their trajectories through the flow, rather than recording velocity at fixed grid points as an Eulerian model does.

Lagrangian particle dispersion model

A Lagrangian particle dispersion model (LPDM) simulates atmospheric transport and dispersion of tracers and pollutants by computing trajectories of many notional particles carried by winds, used in models such as FLEXPART and HYSPLIT.

Lagrangian particle tracking

Lagrangian particle tracking is a simulation method that follows individual virtual particles through time-evolving velocity fields, used to study ocean transport, larval dispersal, microplastics, oil spills, and air-parcel trajectories.

Lagrangian relaxation

Lagrangian relaxation is an optimization method, named by Geoffrion in 1974, that removes difficult constraints and penalizes their violation, producing bounds used inside branch and bound.

Laguerre polynomials

The Laguerre polynomials, also known as Sonin polynomials, are a family of classical orthogonal polynomials introduced by Edmond Laguerre in 1879, used in hydrogen-atom wavefunctions and Gauss–Laguerre quadrature.

Oct 22, 2026

LaH10 superhydride superconductivity

LaH10 superhydride superconductivity is the near-room-temperature superconductivity of lanthanum decahydride, a clathrate hydride with a record transition temperature of about 250 K, first reported in 2018 and confirmed only at megabar pressures.