A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.
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riemanniangeometry× 812
a subfield of Differential Geometry, which specifically studies "Riemannian Manifolds", manifolds with "Riemannian Metrics", which means that they are equipped with continuous i…

st.statistics× 800
Applied, computational and theoretical statistics: e.g. statistical inference, regression, time series, multivariate analysis, data analysis, Markov chain Monte Carlo, design of experiments, case stud…

oa.operatoralgebras× 792
Algebras of operators on Hilbert space, $C^*$algebras, von Neumann algebras, noncommutative geometry

algebraicgroups× 788 
ho.historyoverview× 732
History and philosophy of mathematics, biographies of mathematicians, mathematics education, recreational mathematics, communication of mathematics.

algorithms× 723 
stochasticprocesses× 706
a collection of random variables usually indexed by a totally ordered set.

primenumbers× 696
Questions where prime numbers play a keyrole, such as: questions on the distribution of prime numbers (twin primes, gaps between primes, Hardy–Littlewood conjectures, etc); questions on prime numbers…

arithmeticgeometry× 672 
na.numericalanalysis× 649
Numerical algorithms for problems in analysis and algebra, scientific computation

computationalcomplexity× 637
computational complexity theory; complexity classes, such as P, NP, PSPACE, and so on; resourcelimited computation; NPcompleteness and other completeness concepts; oracle analogues of complexity cla…

sg.symplecticgeometry× 631
Hamiltonian systems, symplectic flows, classical integrable systems

ellipticcurves× 618
an algebraic curve of genus one with some additional properties. Questions with this tag will often have the toplevel tags nt.numbertheory or ag.algebraicgeometry in addition; …

differentialequations× 615
Ordinary or partial differential equations. Delay differential equations, neutral equations, integrodifferential equations. Wellposedness, asymptotic behavior, and related questions.

algebraicnumbertheory× 588 
analyticnumbertheory× 581
A beautiful blending of real/complex analysis with number theory. The study involves distribution of prime numbers and other problems and helps giving asymptotic estimates to these.

differentialtopology× 577
The study of differentiable manifolds and differentiable maps. One fundamental problem is that of classifying manifolds up to diffeomorphism. Differential topology is what Poincaré understood as topol…

fourieranalysis× 576  cohomology× 555 
modularforms× 554
Questions about modular forms and related areas

geometry× 550
Deprecated; please use a more specific tag.

biglist× 520
Questions designed to generate a "big list" of certain results, examples, conjectures, etc. via many individual answers, each contributing one or a few instances. Such a question should typically be i…

banachspaces× 494
a complete normed vector space: A vector space equipped with a norm such that every Cauchy sequence converges.

oc.optimizationcontrol× 466
Operations research, linear programming, control theory, systems theory, optimal control, game theory

modeltheory× 463
the branch of mathematical logic which deals with the connection between a formal language and its interpretations, or models.

probabilitydistributions× 453  algebraiccurves× 449 
discretegeometry× 437
Finite or discrete collections of geometric objects. Packings, tilings, polyhedra, polytopes, intersection, arrangements, rigidity.

qa.quantumalgebra× 432
Quantum groups, skein theories, operadic and diagrammatic algebra, quantum field theory

knottheory× 430
dealing with embedding of curves in manifolds of dimension 3. A knot is a single circle embedded in the affine space of dimension 3 as a smooth curve not crossing itself. Many knot inva…

harmonicanalysis× 420
a generalisation of Fourier analysis that studies the properties of functions. Check out this tag for abstract harmonic analysis (on abelian locally compact groups), or Euclidean …

tagremoved× 415
to be used only when retagging highly(!) offtopic questions where none of the actual tags would make sense; all actual tags the questioner has used are removed and something is needed to…

smoothmanifolds× 411
Smooth manifolds and smooth functions between them. For manifolds with additional structure, see more specific tags, such as [riemanniangeometry]. For more topological aspects, see [differentialtopo…

modulispaces× 402
Given a concrete category C, with objects denoted Obj(C), and an equivalence relation ~ on Obj(C) given by morphisms in C. The moduli set for Obj(C) is the set of equivalence classes with respect to …

highercategorytheory× 399  inequalities× 389 