Kappa

Variant kappa

Greek word καί written with a handwritten variant of kappa, from the Byzantine period

Kappa /ˈkæpə/^[1] (uppercase Κ, lowercase κ or cursive ϰ; Greek: κάππα, káppa) is the 10th letter of the Greek alphabet, used to represent the [k] sound in Ancient and Modern Greek. In the system of Greek numerals, Kʹ has a value of 20. It was derived from the Phoenician letter kaph . Letters that arose from kappa include the Roman K and Cyrillic К.

Greek proper names and placenames containing kappa are often written in English with "c" due to the Romans' transliterations into the Latin alphabet: Constantinople, Corinth, Crete. All formal modern romanizations of Greek now use the letter "k", however.^{[citation needed]}

The cursive form ϰ is generally a simple font variant of lower-case kappa, but it is encoded separately in Unicode for occasions where it is used as a separate symbol in math and science. In mathematics, the kappa curve is named after this letter; the tangents of this curve were first calculated by Isaac Barrow in the 17th century.

Symbol[]

Lowercase (κ)[]

Mathematics and statistics

In graph theory, the connectivity of a graph is given by κ.
In differential geometry, the curvature of a curve is given by κ.
Kappa statistics such as Cohen's kappa and Fleiss' kappa are methods for calculating inter-rater reliability.

Physics

In cosmology, the Einstein gravitational constant is denoted by κ.
In physics, the torsional constant of an oscillator is given by κ.
In physics, the coupling coefficient in magnetostatics is represented by κ.
In fluid dynamics, the von Kármán constant is represented by κ.
In thermodynamics, the compressibility of a compound is given by κ.

Engineering

In structural engineering, κ is the ratio of the smaller factored moment to the larger factored moment and is used to calculate the critical of an unbraced steel member.
In electrical engineering, κ is the multiplication factor, a function of the R/X ratio of the equivalent power system network, which is used in calculating the peak short-circuit current of a system fault. κ is also used to denote conductivity, the reciprocal of resistivity, rho.

Biology and biomedical science

In biology, kappa and kappa prime are important nucleotide motifs for a tertiary interaction of group II introns.
In biology, kappa designates a subtype of an antibody component.
In pharmacology, kappa represents a type of opioid receptor.

Psychology and psychiatry

In psychology and psychiatry, kappa represents a measure of diagnostic reliability.

Economics

In macroeconomics, kappa represents the capital-utilization rate.^{[citation needed]}

Uppercase (Κ)[]

History

In textual criticism, the Byzantine text-type (from Κοινη, Koine, the common text).

Mathematics and statistics

In set theory, kappa is often used to denote an ordinal that is also a cardinal.

Chemistry

In chemistry, kappa is used to denote the denticity of the compound.
In pulping, the kappa number represents the amount of an oxidizing agent required for bleaching a pulp.

Character encodings[]

Character information
Preview	Κ		κ		ϰ		Ⲕ		ⲕ
Unicode name	GREEK CAPITAL LETTER KAPPA		GREEK SMALL LETTER KAPPA		GREEK KAPPA SYMBOL		COPTIC CAPITAL LETTER KAPA		COPTIC SMALL LETTER KAPA
Encodings	decimal	hex	decimal	hex	decimal	hex	decimal	hex	decimal	hex
Unicode	922	U+039A	954	U+03BA	1008	U+03F0	11412	U+2C94	11413	U+2C95
UTF-8	206 154	CE 9A	206 186	CE BA	207 176	CF B0	226 178 148	E2 B2 94	226 178 149	E2 B2 95
Numeric character reference	Κ	Κ	κ	κ	ϰ	ϰ	Ⲕ	Ⲕ	ⲕ	ⲕ
Named character reference	Κ		κ		ϰ, ϰ
DOS Greek	137	89	161	A1
DOS Greek-2	181	B5	228	E4
Windows 1253	202	CA	234	EA
TeX			\kappa

Mathematical Kappa

Character information
Preview	WIKI

[1]