All articles starting with R
22,461 articles
Regressor identifiability analysis
Regressor identifiability analysis is the study of which parameters of a robot's dynamic model can be estimated from measured motion and torque data, yielding the minimum base parameter set.
Regret (I've compilation album)
Regret is a 1999 compilation album by the Sapporo collective I've, the first I've GIRL's COMPILATION volume, collecting PC game theme songs including the Kanon themes.
Regret bound
A regret bound is a theorem in online learning limiting how much worse an algorithm's cumulative loss can be than the best fixed strategy chosen in hindsight.
Regret for the Past
Regret for the Past (伤逝, Shangshi) is a 1925 short story by Chinese writer Lu Xun, his only story on love and marriage, collected in Wandering.
Regret matching
Regret matching is an adaptive rule for choosing actions in repeatedly played games, introduced by Hart and Mas-Colell in 2000, whose play converges to correlated equilibria.
Regret theory
Regret theory is a decision theory in which choices depend on how outcomes compare with what the alternative action would have produced, proposed in 1982.
Regretting You
Regretting You is a 2025 American romantic drama directed by Josh Boone, adapted from Colleen Hoover's 2019 novel, starring Allison Williams as Morgan Grant and Mckenna Grace as her daughter Clara.
Regucalcin
Regucalcin (RGN, SMP30) is a conserved ~33 kDa calcium-binding protein lacking EF-hand motifs, discovered in rat liver in 1978. It regulates calcium pumps and signaling enzymes, is expressed mainly in liver and kidney, and acts as a tumor suppressor.
Regula falsi
Regula falsi, also called the method of false position, is a bracketing root-finding algorithm that uses the secant line through two points straddling a root.
Regular and irregular verbs
Regular and irregular verbs: regular verbs form the past tense with -ed (talk/talked), irregular verbs use idiosyncratic forms (stick/stuck). English irregulars declined from 177 Old English verbs to 98 today, with frequency governing survival.
Regular atrial cardiac myocyte
Regular atrial cardiac myocyte (CL:0002129), also called atrial myocyte or atrial cardiomyocyte, is the working muscle cell of the heart atria; it contracts, conducts impulses, secretes ANP, and lacks the T-tubules and IKur/IKACh currents of ventricular myocytes.
Regular cardinal
A regular cardinal is an infinite cardinal whose cofinality equals itself, meaning it cannot be written as a union of fewer smaller sets; others are singular.
Regular chain (algebra)
In computer algebra, a regular chain is a triangular set of polynomials whose leading coefficients are regular modulo the saturated ideal of earlier polynomials, introduced by Kalkbrener in 1991.
Regular dodecahedron
The regular dodecahedron, also called the pentagonal dodecahedron, is one of the five Platonic solids, with 12 pentagonal faces, 30 edges, and 20 vertices; its dual is the icosahedron.
Regular expression
A regular expression (regex or regexp) is a notation for describing sets of character strings, introduced by Stephen Kleene in 1956 and implemented by Ken Thompson in 1968.
Regular grammar
A regular grammar is a formal grammar whose productions have at most one nonterminal, consistently on one side; such grammars generate exactly the regular languages.
Regular graph
A regular graph is a simple, undirected graph in which every vertex has the same number of neighbors, its degree k; a k-regular graph exists exactly when nk is even.
Regular haircut
Regular haircut: a classic men's style also called a regular taper or businessman's cut, longest on top with scissor-cut sides and back tapering to the natural hairline; related to the military short back and sides.
Regular icosahedron
The regular icosahedron, or gyroelongated pentagonal bipyramid, is one of the five Platonic solids, a convex polyhedron with 20 equilateral triangular faces, 30 edges, and 12 vertices, with five faces meeting at each vertex.
Regular language
A regular language, also called a rational language, is a set of strings recognizable by a finite automaton, the lowest level of the Chomsky hierarchy.
Regular local ring
A regular local ring is a commutative Noetherian local ring whose maximal ideal can be generated by as many elements as its Krull dimension, making it algebraically smooth.
Regular matroid
A regular matroid is a matroid representable by a totally unimodular matrix, one whose subdeterminants are all 0, 1, or −1, making it representable over every field.
Regular octahedron
The regular octahedron is one of the five Platonic solids, with eight equilateral triangular faces, six vertices, and twelve edges, and the cube as its dual.
Regular Palace Attendant
The Regular Palace Attendant (中常侍) was a Han dynasty palace post whose holders attended the emperor in his private quarters and became the main channel of eunuch power.
Regular polygon
A regular polygon, also called a regular 2-polytope, is a plane polygon with all sides and all interior angles equal, one existing for every side count from 3 up.
Regular script
Regular script (楷书, kǎishū) is the standard style of Chinese calligraphy, with straight strokes and roughly square character forms, developed from clerical script around the Later Han.
Regular semigroup
A regular semigroup is a semigroup in which every element a has an inverse b satisfying a = aba, including groups, inverse semigroups, and matrix semigroups.
Regular sequence
A regular sequence is a sequence of ring elements where each is a nonzerodivisor on the module left by the earlier ones, used to define depth.
Regular Show
Regular Show (Un Show Más) is J.G. Quintel's 2010-2017 Cartoon Network animated series about Mordecai and Rigby; it won a 2012 Emmy and returned as The Lost Tapes.
Regular Show: The Lost Tapes
Regular Show: The Lost Tapes is an official 2026 Cartoon Network revival series created by J.G. Quintel, not lost media. Premiered May 11, 2026; 40 episodes greenlit; Pops plays VHS memory tapes in the afterlife as a framing device.