In algebra, an '''operad algebra''' is an "algebra" over an operad. It is a generalization of an associative algebra over a commutative ring ''R'', with an operad replacing ''R''.
== Definitions == Given an operad ''O'' (say, a symmetric sequence in a symmetric monoidal ∞-category ''C''), an '''algebra over an operad''', or '''''O''-algebra''' for short, is, roughly, a left module over ''O'' with multiplications parametrized by ''O''.
If ''O'' is a topological operad, then one can say an algebra over an operad is an ''O''-monoid object in ''C''. If ''C'' is symmetric monoidal, this recovers the usual definition.
Let ''C'' be symmetric monoidal ∞-category with monoidal structure distributive over colimits. If <math>f: O \to O'</math> is a map of operads and, moreover, if ''f'' is a homotopy equivalence, then the ∞-category of algebras over ''O'' in ''C'' is equivalent to the ∞-category of algebras over ''O''' in ''C''.<ref>{{harvnb|Francis|loc=Proposition 2.9.}}</ref>
== See also == *En-ring *Homotopy Lie algebra
== Notes == {{reflist}}
== References == *{{cite web |first=John |last=Francis |url=http://www.math.northwestern.edu/~jnkf/writ/thezrev.pdf |title=Derived Algebraic Geometry Over <math>\mathcal{E}_n</math>-Rings }} *{{cite arXiv|last=Hinich|first=Vladimir|date=1997-02-11|title=Homological algebra of homotopy algebras|arxiv=q-alg/9702015 }} *Vallette, Bruno [https://arxiv.org/pdf/1202.3245 Algebra + homotopy = operad], (2014).
== External links == *{{citation |title=operad |url=http://ncatlab.org/nlab/show/operad |website=ncatlab.org}} *http://ncatlab.org/nlab/show/algebra+over+an+operad
Category:Abstract algebra
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