Physical world and mathematics

Knowledge integration

Knowledge integration is the process of combining knowledge from different disciplines, sectors, or knowledge types into a coherent whole, within a single mind or across a team.

Knowledge-based systems

A knowledge-based system (KBS) is a computer program that solves problems using a stored knowledge base and a separate inference engine, as in expert systems.

Knudsen flow

Knudsen flow is gas transport through pores so narrow, or at such low pressure, that molecules collide with the walls far more often than with each other.

Knudsen number

The Knudsen number (Kn) is a dimensionless number in gas dynamics, the ratio of molecular mean free path to a characteristic flow length, measuring how rarefied the gas is.

Knut Ångström (1857–1910) was a Swedish physicist at Uppsala University who built the standard instruments for measuring solar radiation, and whose 1900 carbon dioxide experiment set back greenhouse climate theory for decades.

Knut Lundmark

Knut Lundmark was a Swedish astronomer who pioneered extragalactic distance measurement, published the first velocity–distance diagram for spiral nebulae, and directed Lund Observatory from 1929.

Knut Urban

Knut Urban, born 1941 in Stuttgart, is a German physicist at Forschungszentrum Jülich who made aberration-corrected electron microscopy practical, winning the Wolf and Kavli prizes.

Knuth–Bendix completion

Knuth–Bendix completion is an algorithm that tries to convert a set of equations into a confluent, terminating rewrite system, deciding the word problem by normal forms.

Knuth's up-arrow notation

Knuth's up-arrow notation, introduced by Donald Knuth in 1976, writes extremely large integers by extending exponentiation to tetration and higher repeated operations, and defines Graham's number.

Koch snowflake

The Koch snowflake, also called the Von Koch snowflake, is a fractal curve attributed to Helge von Koch in 1904, with infinite perimeter but finite area.

Koch's postulates

Koch's postulates, also called the Henle–Koch postulates, are four criteria for establishing that a specific microorganism causes an infectious disease, formulated by German physician Robert Koch in 1890.

Kodaira dimension

Kodaira dimension, also called the Iitaka–Kodaira dimension and written κ, is a birational invariant of algebraic varieties that measures the growth of pluricanonical sections and is the main invariant in the Enriques classification of surfaces.

Kodaira vanishing theorem

The Kodaira vanishing theorem, proved by Kunihiko Kodaira in 1953, states that for a positive line bundle on a compact complex manifold, higher cohomology vanishes.

Koen Vandewal

Koen Vandewal is a Belgian physicist and full professor at Hasselt University, where he chairs the physics department and is known for quantifying voltage losses in organic solar cells.

Sep 20, 2026

Koh Ming Joo

Koh Ming Joo is a Singapore-born organic chemist at the National University of Singapore known for sustainable catalysis with base metals such as iron and nickel.

Kohala, Hawaii

Kohala is the oldest, extinct shield volcano of Hawaiʻi Island, forming the island's northwest peninsula and the North and South Kohala districts, with 5,480-ft summit, 0.7 Ma shield age, Pololū landslide, extreme rainfall gradient, Kohala Ditch, and Kamehameha I's birthplace.

Kohei Tamao

Kohei Tamao (玉尾皓平), born 1942, is a Japanese organosilicon and organoboron chemist, professor at Kyoto University, known for the Tamao oxidation, the Kumada–Tamao coupling, and silole electron-transport materials.

Kohji Matsumoto

Kohji Matsumoto (松本耕二) is a Japanese analytic number theorist, long a professor at Nagoya University, known for zeta-function value-distribution theory and for the Matsumoto zeta-function, a class of polynomial Euler products.

Köhler illumination

Köhler illumination is a microscope illumination method, introduced by August Köhler in 1893, that images the light source into the aperture planes, giving a bright, evenly lit field of view.

Köhler theory

Köhler theory, formulated by Swedish meteorologist Hilding Köhler in 1936, combines the Kelvin and Raoult effects to predict when an aerosol particle activates into a cloud droplet.

Sep 29, 2026

Kohn–Sham equations

The Kohn–Sham equations are self-consistent single-particle equations in density functional theory, introduced by Walter Kohn and Lu J. Sham in 1965 to make DFT practical.

KOI-5715.01

KOI-5715.01 is an unconfirmed transiting planet candidate in NASA's Kepler KOI catalog, about 1.93 Earth radii wide, orbiting the K-type star KOI-5715 every 190 days at 0.6066 astronomical units.

Koichi Mizushima

Koichi Mizushima (水島公一) is a Japanese physicist who, in John Goodenough's Oxford laboratory in 1980, discovered the lithium cobalt oxide cathode on which the lithium-ion battery rests.

Koichi Tanaka

Koichi Tanaka (田中耕一), born 1959 in Toyama City, Japan, is a Japanese analytical chemist at Shimadzu who shared the 2002 Nobel Prize in Chemistry for soft laser desorption.

Koichiro Harada

Koichiro Harada (原田耕一郎) is a Japanese mathematician in finite group theory who gave his name, with Simon Norton, to the Harada–Norton group, a sporadic simple group.

Kōichirō Nishikawa

Kōichirō Nishikawa (西川公一郎; 1949–2018) was a Japanese particle physicist who pioneered long-baseline neutrino oscillation experiments, proposing and leading K2K and founding T2K, work honored by the Breakthrough Prize.

Koichiro Oshima

Koichiro Oshima (大嶌幸一郎) is a Japanese organic chemist and professor at Kyoto University known for cobalt-catalyzed cross-coupling of alkyl halides with Grignard reagents and triethylborane-initiated radical reactions.

Koji Nakanishi

Koji Nakanishi (1925–2019) was a Japanese organic chemist at Columbia University who determined structures of biologically active natural products and developed the exciton chirality method.

Koku (石)

The koku (石) is a traditional Japanese unit of volume, defined since 1891 as 180.39 liters, historically the amount of rice needed to feed one person for a year.