# Tags

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:
 matrix-analysis× 168 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… projective-geometry× 168 operator-theory× 164 Spectrum, resolvent, numerical range, functional calculus, operator semigroups. Special classes of operators: compact, Fredholm, dissipative, differential, integral, pseudodifferential, etc. elliptic-pde× 164 Questions about partial differential equations of elliptic type. Often used in combination with the top-level tag ap.analysis-of-pdes. stable-homotopy× 162 approximation-theory× 160 manifolds× 160 math-philosophy× 157 algebraic-surfaces× 157 computational-geometry× 157 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.algebraic-geometry or mg.metr… birational-geometry× 153 hilbert-spaces× 147 computer-algebra× 145 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.commutative-algeb… semigroups× 145 random-walk× 145 euclidean-geometry× 144 monoidal-categories× 143 textbook-recommendation× 143 Questions asking for recommendations of textbooks on some subject. It can be helpful to indicate whether the request is for self-study, for use in a course one teaches, for use accompanying a course o… langlands-conjectures× 142 Higher reciprocity laws riemann-zeta-function× 142 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… proof-theory× 142 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. l-functions× 137 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 L-functi… universal-algebra× 135 zeta-functions× 135 homology× 134 group-actions× 134 books× 132 Questions in which books play a key-role, such as questions on antique books, e-books, difference between various editions of a book, etc. For questions asking for recommendations of books on some sub… calculus-of-variations× 131 gm.general-mathematics× 131 convex-optimization× 127 class-field-theory× 127 differential-operators× 126 Elliptic, parabolic and hyperbolic operators. Laplace, Laplace-Beltrami, Schrödinger, Dirac. Exterior derivative and Lie derivative operators. intersection-theory× 122 career× 121 graph-colorings× 120 geometric-measure-theory× 116