Algebraic independence

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In algebra, algebraic independence is a property of a set of elements of an extension field E/F, that they satisfy no non-trivial algebraic relation.

Formally, a subset S of E is algebraically independent over F if any polynomial with coefficients in F, say f(X1,...,Xn), such that f(s1,...,sn)=0 where the si are distinct elements of S, must be zero as a polynomial.

If there is a non-zero polynomial f such that f(s1,...,sn)=0, then the si are said to be algebraically dependent.

Any subset of an algebraically independent set is algebraically independent.

An algebraically independent subset of E of maximal cardinality is a transcendence basis for E/F, and this cardinality is the transcendence degree or transcendence dimension of E over F.

Algebraic independence has the exchange property: if G is a set such that E is algebraic over F(G), and I is a subset of G which is algebraically independent, then there is a subset B of G with which is a transcendence basis. The algebraically independent subsets thus form an independence structure.

Examples

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