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: 
motives× 140  algebraicsurfaces× 136  approximationtheory× 134  stablehomotopy× 134 
sobolevspaces× 133 
books× 131
Questions in which books play a keyrole, such as questions on antique books, ebooks, difference between various editions of a book, etc. For questions asking for recommendations of books on some sub…

computeralgebra× 131
Using computers to solve algebraic problems. Questions with this tag should typically include at least one other tag indicating what sort of algebraic problem is involved, such as ac.commutativealgeb…

prooftheory× 130
For question in Proof Theory, where "proofs" themselves are the object of mathematical investigation. It is not to be used to request a proof of some result.

randomwalk× 130 
computationalgeometry× 129
Using computers to solve geometric problems. Questions with this tag should typically have at least one other tag indicating what sort of geometry is involved, such as ag.algebraicgeometry or mg.metr…

textbookrecommendation× 129
Questions asking for recommendations of textbooks on some subject. It can be helpful to indicate whether the request is for selfstudy, for use in a course one teaches, for use accompanying a course o…

hilbertspaces× 125 
ellipticpde× 124
Questions about partial differential equations of elliptic type. Often used in combination with the toplevel tag ap.analysisofpdes.

matrixanalysis× 124
The study of real and complex matrices and their algebraic and analytical properties, including: eigenvalues and eigenvectors, positive definite matrices, matrix inequalities, invariant subspaces, per…

monoidalcategories× 123 
langlandsconjectures× 123
Higher reciprocity laws

semigroups× 123  zetafunctions× 122 
riemannzetafunction× 121
the function of one complex variable $s$ defined by the series $\zeta(s) = \sum_{n \geq 1} \frac{1}{n^s}$ when $\operatorname{Re}(s)>1$. It admits a meromorphic continuati…

homology× 119 
career× 119  birationalgeometry× 119  universalalgebra× 119  euclideangeometry× 118 
gm.generalmathematics× 118 
operatortheory× 117
Spectrum, resolvent, numerical range, functional calculus, operator semigroups. Special classes of operators: compact, Fredholm, dissipative, differential, integral, pseudodifferential, etc.

intersectiontheory× 114  calculusofvariations× 112 
linearprogramming× 108 
lfunctions× 107
Questions about generalizations of the Riemann Zeta function of arithmetic interest whose definition relies on meromorphic continuation of special kinds of Dirichlet series, such as Dirichlet Lfuncti…

classfieldtheory× 107  groupactions× 107 
notation× 106  diophantineapproximation× 105  permutations× 102 
invarianttheory× 101
Invariant theory deals with an algebraic, geometric or analytic structure X , submited to the action of an (algebraic) group G . It studies Ginvariant elements of X as well as the set of Gorbits.
