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Fingering instability
Fingering instability, also called wetting front instability, is the breakup of a planar wetting front into narrow wetting fingers during infiltration into unsaturated soil, which speeds water and solute movement to groundwater.
Finite difference
A finite difference, also known as the calculus of differences, is a difference between a function's values at nearby points, used to approximate derivatives numerically.
Finite difference method
The finite difference method (FDM) is a numerical technique for solving differential equations by replacing derivatives with difference quotients on a grid, turning the problem into algebraic equations solved simultaneously.
Finite element method
The finite element method (FEM), also known as finite element analysis, is a numerical technique that solves partial differential equations by subdividing a domain into simple finite elements.
Finite element method in structural mechanics
The finite element method in structural mechanics is a numerical technique for solving elasticity equations by dividing a structure into small elements and assembling their equations.
Finite field
A finite field, also called a Galois field, is a field with a finite number of elements. Its order is always a prime power, and one such field exists for each.
Finite field arithmetic
Finite field arithmetic, also called Galois field arithmetic, is arithmetic in a field with a finite number of elements rather than in infinite fields like the rationals.
Finite geometry
Finite geometry is the branch of geometry that studies geometric structures with finitely many points, notably projective and affine spaces over finite fields, with applications to coding theory and cryptography.
Finite group
A finite group is a group containing only finitely many elements, the count being its order. Finite groups model symmetries of finite objects and arise throughout mathematics and physics.
Finite integration technique
The finite integration technique (FIT) is a numerical method for computational electromagnetics, proposed by Thomas Weiland in 1977, that discretizes Maxwell's equations in integral form on dual interlaced grids.
Finite model property
The finite model property (FMP) is a property of a logic: every satisfiable formula has a finite model, giving a standard route to proving decidability in modal logic.
Finite potential well
The finite potential well, also called the finite square well, is a quantum mechanics model problem whose finite-depth walls confine a particle with finitely many bound levels.
Finite set
A finite set is a set whose elements can be counted with a natural number n; the number n is the set's cardinality, and any set that is not finite is infinite.
Finite volume method
The finite volume method (FVM) is a numerical technique that solves partial differential equations by enforcing integral conservation laws over a mesh of control volumes.
Finite-difference time-domain method
The finite-difference time-domain (FDTD) method, also known as Yee's method, is a numerical technique for solving Maxwell's equations, introduced by Kane S. Yee in 1966.
Finite-key security analysis in quantum key distribution
Finite-key security analysis is the branch of quantum key distribution security theory that proves secrecy of keys from finite signal blocks, quantifying how statistical fluctuations reduce extractable key length.
Finite-size scaling
Finite-size scaling (FSS) is the universal behavior of large but finite systems near a continuous phase transition, letting critical properties of the infinite system be extracted from finite samples.
Finite-variable infinitary logic
Finite-variable infinitary logic, L^k∞ω, allows infinitely long conjunctions and disjunctions but limits formulas to at most k variables, and its union over all finite k is the main yardstick of expressiveness in finite model theory.
Finitely generated group
A finitely generated group is a group whose every element is a product of powers of elements from some finite generating set, a basic finiteness condition in group theory.
Finitely generated module
A finitely generated module is a module expressible as combinations of finitely many elements, the analog of a spanning set in linear algebra over general rings.
Finitism
Finitism is a position in the philosophy of mathematics, due to David Hilbert, restricting reasoning to finite, executable arguments; it underpinned his program for proving mathematics consistent.
Finnish Meteorological Institute
The Finnish Meteorological Institute (Ilmatieteen laitos) is Finland's national meteorological service and research institute under the Ministry of Transport and Communications, tracing its origins to 1838.
Fins
A fin, or extended surface, is a slender projection attached to a hot body to increase surface area for heat transfer, as in heat sinks and heat exchangers.
Finsler metric
A Finsler metric is a function assigning each tangent vector its length, generalizing Riemannian metrics by dropping the quadratic restriction; Paul Finsler introduced it in 1918.
Fiona A. Harrison
Fiona A. Harrison is an experimental astrophysicist at Caltech who leads NASA's NuSTAR mission, the first focusing high-energy X-ray telescope in orbit, launched in 2012.
Fiona C. Meldrum
Fiona C. Meldrum is a British materials chemist who holds the chair in Inorganic Chemistry at the University of Leeds, known for bio-inspired crystallization research.
FIPS 203
FIPS 203 is a NIST standard, published August 13, 2024, that specifies ML-KEM, a key-encapsulation mechanism derived from CRYSTALS-Kyber and intended to protect general encryption against quantum computers.
FIPS 204
FIPS 204, the Module-Lattice-Based Digital Signature Standard, was published by NIST on August 13, 2024, specifying ML-DSA, a quantum-resistant digital signature algorithm derived from CRYSTALS-Dilithium.
FIPS 205
FIPS 205, the Stateless Hash-Based Digital Signature Standard, is a 2024 NIST standard specifying SLH-DSA, a hash-based signature scheme derived from SPHINCS+ that resists quantum attack.
Fire
Fire is a rapid oxidation process, a chemical reaction between fuel and an oxidizer that releases heat and light, requiring fuel, oxygen, heat, and an uninhibited chain reaction.