6,052 articles
Tu quoque
Tu quoque (Latin for "you too"), also called the appeal to hypocrisy, is an ad hominem fallacy dismissing an argument because its speaker does not practice it.
Tucker decomposition
The Tucker decomposition, or Tucker3, is a tensor decomposition expressing a tensor as a core tensor multiplied by factor matrices, introduced by L. R. Tucker in 1963.
Tucker's lemma
Tucker's lemma is a combinatorial theorem, equivalent to the Borsuk–Ulam theorem, stating that any antipodal labeling of a symmetrically triangulated ball forces an edge with opposite labels.
Tukey's range test
Tukey's range test, usually called Tukey's HSD, is a multiple comparison procedure that compares all pairs of group means after an analysis of variance while controlling the family-wise error rate.
Tunicate swarm algorithm
The tunicate swarm algorithm (TSA) is a swarm-based metaheuristic for derivative-free global optimization, introduced in 2020 and modeled on the jet propulsion and foraging of marine tunicates.
Tuple
A tuple, also called an ordered n-tuple, is a finite ordered list of elements, written (1, 2, 3), in which order and repetition count; tuples of two and three elements are called ordered pairs and triples.
Tupper's self-referential formula
Tupper's self-referential formula is an inequality published by computer scientist Jeff Tupper in 2001 which, plotted over a particular 106-by-17 pixel block, draws a bitmap picture of itself.
Turán graph
The Turán graph T(n, r) is the complete multipartite graph on n vertices with parts as equal as possible, giving the most edges among graphs with no K{r+1}.
Turán number
The Turán number ex(n, F) is the maximum number of edges in an n-vertex graph or hypergraph containing no copy of F, central to extremal graph theory.
Turán's theorem
Turán's theorem is a 1941 result of Pál Turán stating that the graph on n vertices with no complete subgraph on r+1 vertices and the most edges is the Turán graph.
Turing completeness
Turing completeness, also known as computational universality, is the property of a computational system that can simulate any Turing machine, so it can compute anything computable given unbounded memory and time.
Turing degree
A Turing degree is an equivalence class of sets of natural numbers under relative computability, the central object of computability theory, with the halting problem at degree 0'.
Turing jump
The Turing jump of a set X is the halting problem relative to X, a set computably enumerable from X but strictly harder to decide than X.
Turing reduction
A Turing reduction shows one decision problem is no harder than another: membership is decided by an algorithm that queries an oracle for the other problem in single steps.
Turkish Statistical Institute
The Turkish Statistical Institute (Türkiye İstatistik Kurumu, TÜİK) is Turkey's scientifically autonomous national statistical agency, headquartered in Ankara, founded in 1926 and producing official statistics under Law No. 5429 of 2005.
Tutte polynomial
The Tutte polynomial, named for mathematician and codebreaker W. T. Tutte, is a two-variable invariant of graphs and matroids whose evaluations count spanning trees, acyclic orientations, and proper colorings.
Tweedie distribution
The Tweedie distributions are a family of exponential dispersion models where variance is a power of the mean, including the normal, Poisson, gamma, and inverse Gaussian as special cases.
Twin prime
Twin primes, or prime pairs, are pairs of primes differing by exactly 2, like (3, 5) and (5, 7); whether infinitely many exist is an open conjecture.
Twin prime conjecture
The twin prime conjecture states that there are infinitely many primes p such that p + 2 is also prime, as in (3, 5) and (11, 13). It remains unproven.
Twin prime constant
The twin prime constant C₂ is a mathematical constant equal to about 0.66016, which measures how often pairs of primes two apart are expected to occur.
Twin primes
Twin primes are pairs of prime numbers separated by exactly 2, like (3, 5) and (11, 13); whether infinitely many exist is a famous open problem.
TWINSPAN
TWINSPAN (Two-Way Indicator Species Analysis) is a hierarchical, divisive classification method for community ecology data, introduced by M. O. Hill in 1979 as a FORTRAN program.
Two-dimensional space
Two-dimensional space, also called bi-dimensional space, is a mathematical space in which every point is specified by two coordinates, the standard example being the Euclidean plane of elementary geometry.
Two-dimensional warranty models
A two-dimensional warranty model covers a product until an age limit or a usage limit is reached, whichever comes first, as in 5 years or 40,000 miles.
Two-graph
A two-graph is a combinatorial structure of vertices and triples of them such that every set of four vertices contains an even number of selected triples.
Two-proportion Z-test
The two-proportion z-test, also called the two-sample proportion z-test, is a statistical hypothesis test comparing success rates between two independent groups, used in clinical trials and A/B testing.
Two-sided Laplace transform
The two-sided Laplace transform, also called the bilateral Laplace transform, is an integral transform integrating over the whole real line, used for non-causal signals and linear time-invariant systems.
Two-stage cluster sampling
Two-stage cluster sampling is a survey design in which clusters are sampled first and units subsampled within each, cutting fieldwork cost for dispersed populations while losing precision.
Two-stage sampling
Two-stage sampling is a probability sampling design that first samples larger units, such as census enumeration areas, then samples smaller units, such as households, within them.
Two-stage stochastic optimization
Two-stage stochastic optimization, also called stage stochastic optimization, is an operations research method splitting decisions into first-stage actions and second-stage recourse after uncertainty is observed.