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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motives× 201 
computationalgeometry× 199
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…

stablehomotopy× 197  algebraicsurfaces× 196 
hilbertspaces× 196
a real or complex vector space endowed with an inner product such that $H$ is a complete metric space when endowed with the norm induced by this inner product.

hodgetheory× 195  combinatorialgeometry× 194  birationalgeometry× 193 
characteristicp× 189  manifolds× 188 
riemannzetafunction× 188
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…

euclideangeometry× 186 
teaching× 186
For questions related to teaching mathematics. For questions in Mathematics Education as a scientific discipline there is also the tag mathematicseducation. Note you may also ask your question on htt…

randomwalk× 182 
textbookrecommendation× 178
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…

monoidalcategories× 177 
groupactions× 175 
mathphilosophy× 174
Philosophical aspects of logic and set theory; truth status of mathematical axioms; Philosophy of Mathematics; philosophical aspects of mathematics in general; relation of mathematics to philosophy; e…

eigenvalues× 173  semigroups× 169 
differentialoperators× 168
Elliptic, parabolic and hyperbolic operators. Laplace, LaplaceBeltrami, Schrödinger, Dirac. Exterior derivative and Lie derivative operators.

graphcolorings× 167 
lfunctions× 167
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…

calculusofvariations× 164 
prooftheory× 162
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.

spectralgraphtheory× 162
Questions related to the spectrum of graphs, defined using one of the possible variants of the discrete Laplace operator or Laplacian matrix.
See https://en.wikipedia.org/wiki/Discrete_Laplace_oper…

geometricmeasuretheory× 161
Questions about geometric properties of sets using measure theoretic techniques; rectifiability of sets and measures, currents, Plateau problem, isoperimetric inequality and related topics.

computeralgebra× 159
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…

langlandsconjectures× 158
Higher reciprocity laws

planegeometry× 157 
permutations× 156
Questions related to permutations, bijections from a finite (or sometimes infinite) set to itself.

classfieldtheory× 156 
universalalgebra× 155
The study of algebraic structures and properties applying to large classes of such structures. For example, ideas from group theory and ring theory are extended and considered for structures with oth…

zetafunctions× 153  homology× 153  intersectiontheory× 152 