42,772 articles
Kriging
Kriging is a family of geostatistical interpolation techniques that predicts values at unsampled locations as weighted averages of nearby observations, named after mining engineer Danie G. Krige.
Krijn P. de Jong
Krijn P. de Jong, also known as K.P. de Jong, is a Dutch materials chemist and emeritus professor of inorganic chemistry and catalysis at Utrecht University, born in 1954.
Kripke semantics
Kripke semantics, also known as relational semantics, is the standard formal semantics for modal logic, in which formulas are evaluated at possible worlds, introduced by Saul Kripke in 1959.
Kripke–Platek set theory
Kripke–Platek set theory (KP) is a weak axiomatic set theory introduced independently by Saul Kripke and Richard Platek in the 1960s; its transitive models are called admissible sets.
Krische allylation
The Krische allylation is an iridium-catalyzed reaction, introduced by Michael Krische in 2008, that adds an allyl group to aldehydes or alcohols without preformed allylmetal reagents.
Krishnan Raghavachari
Krishnan Raghavachari is an Indian-born theoretical and computational chemist, Distinguished Professor at Indiana University, best known as principal author of the CCSD(T) method, the gold standard of quantum chemistry.
Kristian Birkeland
Kristian Birkeland (1867–1917) was a Norwegian physicist whose 1896 solar-particle theory of the aurora founded space plasma physics, and who co-invented the Birkeland–Eyde nitrogen fixation process behind Norsk Hydro's fertilizer industry.
Kristian Sommer Thygesen
Kristian Sommer Thygesen, also published as Kristian S. Thygesen, is a computational materials scientist and professor at the Technical University of Denmark, leading the open C2DB database of 2D materials.
Kristie Boering
Kristie Boering is an atmospheric chemist and Templeton Professor at UC Berkeley, elected to the National Academy of Sciences in 2018, known for isotope tracers of atmospheric chemistry.
Kristin DeWitt
Kristin DeWitt, known as Kristy DeWitt, is an American physical chemist who led IARPA chemical-detection programs and joined the U.S. Naval Research Laboratory in 2021.
Kristin Persson
Kristin A. Persson is a professor of materials science at UC Berkeley and, since 2011, director of the Materials Project, an open database of computed materials properties.
Kristin Poinar
Kristin Poinar is an American glaciologist at the University at Buffalo who models meltwater flow through the Greenland Ice Sheet, combining modeling, fieldwork, and deep learning.
Kristina B. Katsaros
Kristina B. Katsaros is a Swedish-born atmospheric scientist known for air-sea interaction research and satellite microwave remote sensing of cyclones, directing NOAA's AOML from 1997 to 2003.
Kristopher McNeill
Kristopher McNeill, born 1970 in Tucson, Arizona, is an environmental chemist who has been Professor of Environmental Chemistry at ETH Zurich since 2009, after a decade at the University of Minnesota.
Kronecker delta
The Kronecker delta, written δij, is a mathematical symbol that equals 1 when its two indices are equal and 0 otherwise, serving as the index-notation form of the identity matrix.
Kronecker product
The Kronecker product, also called the tensor product of matrices, replaces each entry of a matrix A with A's entry times matrix B, yielding a block matrix.
Kronecker–Weber theorem
The Kronecker–Weber theorem, sometimes called the Kronecker–Weber–Hilbert theorem, states that every finite abelian extension of the rationals lies inside a cyclotomic field, an early result of class field theory proved by Hilbert in 1896.
Krori–Barua solution
The Krori–Barua solution is a singularity-free exact solution of the Einstein–Maxwell equations describing a static, spherically symmetric charged fluid sphere, published by K. D. Krori and J. Barua in 1975.
Krull dimension
The Krull dimension of a commutative ring is the supremum of the lengths of chains of prime ideals, defined by Wolfgang Krull in 1928 as the standard notion of dimension in commutative algebra.
Kruskal–Szekeres coordinates
Kruskal–Szekeres coordinates, also known as Kruskal coordinates, are coordinates on Schwarzschild spacetime, introduced independently by Martin Kruskal and George Szekeres in 1960, in which the metric is regular at the event horizon.
Kruskal–Wallis test
The Kruskal–Wallis test is a nonparametric statistical test that decides whether three or more independent groups come from the same distribution by comparing pooled rank sums, introduced in 1952.
Kruskal's algorithm
Kruskal's algorithm is a greedy algorithm that finds a minimum spanning tree of any connected, weighted, undirected graph, published by Joseph B. Kruskal in 1956.
Kruskal's tree theorem
Kruskal's tree theorem is a 1960 result in well-quasi-order theory, proved by J. B. Kruskal, stating that finite trees over a well-quasi-ordered label set are well-quasi-ordered under homeomorphic embedding.
Krylov complexity
Krylov complexity, also called K-complexity, is a parameter-free measure in quantum many-body physics of how far a time-evolving operator spreads along the Krylov basis generated by the Lanczos algorithm, used as a diagnostic of quantum chaos.
Krylov subspace
A Krylov subspace is the vector space spanned by b, Ab, A²b, and so on for a matrix A, named for Aleksey Krylov in 1931.
Krylov subspace methods
Krylov subspace methods are iterative projection methods for large linear systems, eigenvalue problems, and matrix functions, building approximations from repeated matrix-vector products; examples include CG, GMRES, and BiCGSTAB.
Krypton
Krypton (symbol Kr, atomic number 36) is a colorless, odorless noble gas in Earth's atmosphere, used in fluorescent lamps, the krypton fluoride laser, and defining the meter from 1960 to 1983.
Krypton difluoride
Krypton difluoride (KrF₂) is a colorless crystalline compound of krypton and fluorine, first prepared in 1963, thermodynamically unstable, and among the strongest oxidative fluorinating agents known, able to oxidize gold and xenon below room temperature.
Krypton fluoride laser
A krypton fluoride (KrF) laser is an excimer laser emitting 248 nm deep ultraviolet light from krypton and fluorine gas; it was the first DUV lithography light source.
Krypton-85
Krypton-85 is a radioactive krypton isotope with a half-life of about 10.7 years, produced by nuclear fission, released during spent-fuel reprocessing, and used as an atmospheric tracer.