mathematics, suppose ).C is a collection of mathematical objects (for instance sets or functions Then we say that C is rigid if every c ∈ C is uniquely determined by less information about c than one would expect. Wikibooks Wikiversity has more about this subject: School of Mathematics Wikiquote has a collection of quotations related to: Mathematics Look up Mathematics on Wiktionary, the free dictionary Wikimedia Commons has media related to: Mathematics Bogomolny, Alexander: Interactive Mathematics Miscellany and Puzzles. ...

It should be emphasized that the above statement does not define a mathematical property. Instead, it describes in what sense the adjective rigid is typically used in mathematics, by mathematicians.

Some examples include:

1. Harmonic functions on the unit disk are rigid in the sense that they are uniquely determined by their boundary values.
2. By the fundamental theorem of algebra, polynomials in C are rigid in the sense that any polynomial is completely determined by its values on any countably infinite set, say N, or the unit disk.
3. Linear maps L(X,Y) between vector spaces X, Y are rigid in the sense that any L ∈ L(X,Y) is completely determined by its values on any set of basis vectors of X.
4. Mostow's rigidity theorem

This article incorporates material from rigid on PlanetMath, which is licensed under the GFDL. In mathematics, mathematical physics and the theory of stochastic processes, a harmonic function is a twice continuously differentiable function f : U → R (where U is an open subset of Rn) which satisfies Laplaces equation, i. ... In mathematics, the fundamental theorem of algebra states that every complex polynomial of degree has exactly roots (zeros), counted with multiplicity. ... In mathematics, polynomial functions, or polynomials, are an important class of simple and smooth functions. ... An infinite set in Cantors set theory is any set which is not finite. ... A disc of unit radius on a plane is called a unit disc. ... In mathematics, a subset B of a vector space V is said to be a basis of V if it satisfies one of the four equivalent conditions: B is both a set of linearly independent vectors and a generating set of V. B is a minimal generating set of V... In mathematics, Mostows rigidity theorem, sometimes called the strong rigidity theorem, is a strong statement about the isomorphisms of negatively curved manifolds which follows from rather weak assumptions about their structure. ... PlanetMath is a free, collaborative, online mathematics encyclopedia. ...