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.
A distribution is a continuous linear functional on the space $\mathcal{C}^{\infty}_c$ of smooth (indefinitely differentiable) functions with compact support. Though they appeared in formal computati…
Equidecomposability of polyhedra under cutting-and-pasting along faces, and generalizations. Hilbert's third problem, Dehn's invariants. Homological developments motivated by these issues.
Surfaces bounding a knot or a link.
Questions about Selberg class and the related conjectures such as the analogue of Riemann Hypothesis, Selberg's orthonormality conjecture, degree conjecture, general converse conjecture that says the …
Semiabelian categories are pointed exact protomodular categories with coproducts. Suitable for questions about protomodular categories as well.
Semialgebraic geometry is the study of inequalities expressible in algebraic functions in one or several variables, usually over the real numbers or some field with similar properties.
Semidefinite programming can be regarded as an extension of linear programming. In a semidefinite program, the goal is to optimize a linear function over the intersection of the cone of positive semi…
A semigroup is a set $S$ together with a binary operation that is associative. Examples of semigroups are the set of finite strings over a fixed alphabet (under concatenation) and the positive integer…
(Usually one-parameter) semigroups of linear operators and their applications to partial differential equations, stochastic processes such as Markov processes and other branches of mathematics.
Manifolds with a non-degenerate symmetric bilinear form in each tangent space varying differentiably but with constant index and signature.
For questions about separable algebras over commutative rings, separable ring extensions, Azumaya algebras, finite etale algebras.
for questions about sequences and series, e.g. convergence, closed form expressions, etc. Note that there is a different tag for spectral sequences, and also note that MathOverflow is not for homework…
Serre duality is a duality present on non-singular projective algebraic varieties V of dimension n (and in greater generality for vector bundles and further, for coherent sheaves)
forcing, large cardinals, descriptive set theory, infinite combinatorics, cardinal characteristics, forcing axioms, ultrapowers, measures, reflection, pcf theory, models of set theory, axioms of set t…
Questions about maps into the powerset of a set (called set-valued maps, multivalued maps, or relations), corresponding concepts of continuity (like upper and lower semicontinuity), inclusion problems…
Hamiltonian systems, symplectic flows, classical integrable systems
For questions about sheaves on a topological space.