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Logical conjunction
Logical conjunction, also called logical and, is the two-place logical operation written ∧ that combines two statements into a compound true only when both are true.
Logical connective
A logical connective, or logical operator, is a symbol such as "and", "or", "not", or "if...then" that binds one or more sentences into a new compound sentence in formal logic.
Logical disjunction
Logical disjunction, also called the inclusive or, is the logical connective written ∨, a compound sentence true when at least one of its two disjuncts is true.
Logical NOR
Logical NOR, also called joint denial, is the logical connective true only when both of its statements are false; on its own it can express every truth-function of propositional logic.
Logical reasoning
Logical reasoning is the process of drawing conclusions from premises by rules evaluated independently of subject matter, divided into deductive, inductive, and abductive modes, first formally studied by Aristotle.
Logical relations
A logical relation is a family of relations between program meanings, indexed by types and defined by recursion over type structure; it proves program equivalence and compiler correctness.
Logistic distribution
The logistic distribution, also known as the sech-squared distribution, is a continuous probability distribution with a sigmoid cumulative distribution function, resembling the normal distribution but with heavier tails.
Logistic function
The logistic function, also known as the Verhulst equation or logistic sigmoid, is the S-shaped function mapping real numbers into (0, 1), devised by Verhulst in 1838.
Logistic map
The logistic map, also called the discrete logistic equation, is a recurrence widely used in nonlinear dynamics, passing through stable states, period doubling, and chaos as the parameter r increases.
Logistic regression
Logistic regression, also called the logit or binary logit model, is a statistical method for modeling the probability of a binary outcome as a function of explanatory variables.
Logit
The logit, also called the log-odds, is a statistical function that converts a probability into the logarithm of its odds; it is the link function of logistic regression.
Lonely runner conjecture
The Lonely Runner Conjecture, or lonely runner problem, is an unsolved number theory problem posed by Jörg M. Wills in 1967 concerning runners on a unit circle.](20 words)
Long and short scales
The long and short scales are two competing systems for naming large numbers: in the short scale each new term is 1,000 times the previous one, in the long scale 1,000,000 times.
Long division
Long division is a standard method for dividing multi-digit numbers by hand, breaking the problem into a series of steps and allowing arbitrarily large numbers to be computed on paper.
Long tail
The long tail, or long-tailed distribution, is a probability distribution whose right tail decays so slowly that shifting the threshold barely changes the tail probability.
Longest path problem
The longest path problem is the NP-hard problem of finding a maximum-length simple path in a graph, solvable in linear time on directed acyclic graphs and applied to project scheduling.
Longitudinal data analysis
Longitudinal data analysis is the collection of statistical methods for data measured repeatedly on the same subjects over time, separating within-subject change from between-subject differences.
Longitudinal mediation analysis
Longitudinal mediation analysis is a family of statistical methods for estimating direct and indirect effects when the mediator, the outcome, or both are measured repeatedly over time.
Look-and-say sequence
The look-and-say sequence, also called the Conway sequence or audioactive decay, is an integer sequence where each term describes the previous one, giving 1, 11, 21, 1211, 111221.
Loop algebra
A loop algebra is an infinite-dimensional Lie algebra formed from a Lie algebra by extending its scalars to Laurent polynomials, and it underlies affine Kac-Moody algebras.
Loop space
The loop space ΩY of a pointed topological space Y is the space of loops in Y that start and end at the base point.
Lorena Bociu
Lorena Bociu is an applied mathematician, Professor and Associate Department Head at North Carolina State University, known for optimal control of partial differential equations and a 2019 PECASE award.
Lorentzian manifold
A Lorentzian manifold is a smooth manifold carrying a metric of Lorentzian signature, with one negative direction; with its metric it models spacetime in general relativity.
Lorenz system
The Lorenz system is a set of three nonlinear differential equations introduced by meteorologist Edward Lorenz in 1963 as the canonical example of deterministic chaos.
Loss function
A loss function, also called a criterion function, assigns a numerical penalty to the gap between a prediction, estimate, or decision and the truth, in statistics and machine learning.
Lovász conjecture
The Lovász conjecture is an open problem in graph theory stating that every finite connected vertex-transitive graph has a Hamiltonian path, posed by László Lovász in 1969.
Lovász local lemma
The Lovász local lemma is a 1975 result of Erdős and Lovász: if bad events each have small probability and limited dependence, none may occur with positive probability.
Low-density parity-check code
A low-density parity-check (LDPC) code is an error-correcting code defined by a sparse parity-check matrix, proposed by Robert G. Gallager at MIT in 1960 and used in 5G, Wi-Fi, and satellite broadcasting.
Low-rank approximation
A low-rank approximation replaces a matrix with one of much lower rank that preserves its dominant structure, used for compression, denoising, and fast linear algebra on large data matrices.
Löwenheim–Skolem theorem
The Löwenheim–Skolem theorem is a pair of results in model theory of first-order logic, proved by Löwenheim in 1915 and Skolem in 1922.