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.
Type to find tags: 
liealgebras× 772
algebraic structures which were introduced to study the concept of infinitesimal transformations. The term "Lie algebra" (after Sophus Lie) was introduced by Hermann Weyl in the 1930s…

riemanniangeometry× 762
a subfield of Differential Geometry, which specifically studies "Riemannian Manifolds", manifolds with "Riemannian Metrics", which means that they are equipped with continuous i…

oa.operatoralgebras× 761
Algebras of operators on Hilbert space, C^*algebras, von Neumann algebras, noncommutative geometry

algebraicgroups× 759 
ho.historyoverview× 714
History and philosophy of mathematics, biographies of mathematicians, mathematics education, recreational mathematics, communication of mathematics.

algorithms× 689 
stochasticprocesses× 664
a collection of random variables usually indexed by a totally ordered set.

primenumbers× 661
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× 656 
na.numericalanalysis× 624
Numerical algorithms for problems in analysis and algebra, scientific computation

computationalcomplexity× 623
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…

ellipticcurves× 597
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; …

sg.symplecticgeometry× 597
Hamiltonian systems, symplectic flows, classical integrable systems

geometry× 593
Deprecated; please use a more specific tag.

differentialequations× 586
Ordinary or partial differential equations. Delay differential equations, neutral equations, integrodifferential equations. Wellposedness, asymptotic behavior, and related questions.

differentialtopology× 553
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…

algebraicnumbertheory× 551  fourieranalysis× 540 
analyticnumbertheory× 533
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.

cohomology× 524 
modularforms× 522
Questions about modular forms and related areas

biglist× 501
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× 469
a complete normed vector space: A vector space equipped with a norm such that every Cauchy sequence converges.

oc.optimizationcontrol× 452
Operations research, linear programming, control theory, systems theory, optimal control, game theory

modeltheory× 446
the branch of mathematical logic which deals with the connection between a formal language and its interpretations, or models.

probabilitydistributions× 426 
qa.quantumalgebra× 426
Quantum groups, skein theories, operadic and diagrammatic algebra, quantum field theory

algebraiccurves× 419 
tagremoved× 417
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…

knottheory× 410
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…

modulispaces× 385
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 …

smoothmanifolds× 384
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…

highercategorytheory× 384  harmonicanalysis× 382 
discretegeometry× 378
Finite or discrete collections of geometric objects. Packings, tilings, polyhedra, polytopes, intersection, arrangements, rigidity.

kt.ktheoryhomology× 373
Algebraic and topological Ktheory, relations with topology, commutative algebra, and operator algebras
