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:
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Questions on the evaluation of derivatives or problems involving derivatives (for example, use of the mean value theorem).
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for questions about rings, which are a type of algebraic structure studied in abstract algebra and algebraic number theory.
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Questions about commutative rings, their ideals, and their modules.
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Questions about algebraic methods and invariants to study and classify topological spaces: homotopy groups, (co)-homology groups, and beyond.
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Questions on "Partial Differential Equations", as opposed to "ordinary differential equations".
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For questions that don't admit a definitive answer but still are relevant to this site. Please be specific about what you are after.
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Convergence of sequences and different modes of convergence.
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the process of choosing the "best" value among possible values. They are often formulated as questions on the minimization/maximization of functions, with or without constraints.
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Mathematical questions about Algorithms, including the Analysis of Algorithms, Combinatorial Algorithms, proofs of correctness, invariants, and semantic analyses
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For questions about approaches and techniques for discovering a proof, as opposed to writing it down clearly (which involves (proof-writing)). Should not be used unless the focus is on the technique o…
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For questions about vector spaces and their properties. More general questions about linear algebra belong under the [tag:linear-algebra] tag. A vector space is a space which consists of elements call…
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refers to questions asked in the field of Group Theory which, in particular, focus on the groups of finite order.
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Questions about the evaluation of specific definite integrals.
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Questions on numerical analysis/numerical methods; methods for approximately solving various problems that often do not admit exact solutions.
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A stochastic, or random, process describes the correlation or evolution of random events. It is used to model stock market fluctuations and electronic/audio-visual/biological signals. Among the most w…
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Questions involving complex numbers: numbers of the form $a+bi$ where $i^2=-1$.
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Question on the meaning, history, and usage of mathematical symbols and notation. Please remember to mention where (book, paper, webpage, etc.) you encountered any mathematical notation you are asking…
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studied in category theory using properties of objects and morphisms between them. Many constructions are special cases of categorical limits and colimits (e.g. products in var…
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sets on which you can measure the "distance" between any two points. The distance measurement is generally required to be symmetric (so distance from $A$ to $B$ is the same as distan…
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natural numbers not divisible by any smaller number other than 1. This tag is intended for questions about, related to, or involving prime numbers.
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Fourier analysis, also known as spectral analysis, encompasses all sorts of Fourier expansions, including Fourier series, Fourier transform and the discrete Fourier transform (and relatives). The non-…
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for questions about fields and field theory in abstract algebra. A field is, roughly speaking, an algebraic structure in which addition, subtraction, multiplication, and division of eleme…
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for set theory topics typically studied at the advanced undergraduate or graduate level. These include cofinality, axioms of ZFC, axiom of choice, forcing, set-theoretic independence, larg…
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Questions about evaluating summations, especially finite summations. For infinite series, please consider the (sequences-and-series) tag instead.
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For questions about the writing of proofs. But instead of focusing the mathematics behind the proof, these questions ask about the details and implementation of the proof.
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For questions concerning a specific proof, asking for verification, identifying errors, suggestions for improvement, etc.
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Questions on the usage and meaning of words in mathematics, the names for mathematical entities, and other such questions.
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one where small changes of input result in correspondingly small changes of output. Use this tag for questions involving this concept. As there are many mathemati…
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numbers associated to a linear operator from a vector space $V$ to itself: $\lambda$ is an eigenvalue of $T\colon V\to V$ if the map $x\mapsto \lambda x-Tx$ is not injective. An eigenv…
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a system of integer arithmetic based on the congruence relation $a \equiv b \pmod{n}$ which means that $n$ divides $b-a$.
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Representation theory studies (among else) representations of groups by finite matrices. The non-commutative analog of classical Fourier transforms.
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Questions related to real and complex logarithms.
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For questions about modules over rings, concerning either their properties in general or regarding specific cases.
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Questions on basic arithmetic, e.g. addition, subtraction, multiplication, division, powers, radicals, etc.
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the inference from the particular to the general. Mathematical induction is not true induction, but is a form of deductive reasoning. Its most common use is induction over wel…
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Questions involving asymptotic analysis, including growth of functions, Big-O notation, Big-Omega and Big-Theta notations.