18.11.2012 Views

Symmetric Monoidal Categories for Operads - Index of

Symmetric Monoidal Categories for Operads - Index of

Symmetric Monoidal Categories for Operads - Index of

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

10.1 Enveloping <strong>Operads</strong> and Algebras 141<br />

Furthermore, the morphism η : R → R[ · ] induces a morphism <strong>of</strong> operads<br />

η : R → SR(R[ · ],A)<br />

so that SR(R[ · ],A) <strong>for</strong>ms an operad under R. As a conclusion, we obtain that<br />

the map SR(R[ · ]) : A ↦→ SR(R[ · ],A) defines a functor SR(R[ · ]) : RE →R / OE.<br />

Our goal, announced in the introduction, is to prove:<br />

10.1.3 Theorem. For every R-algebra A ∈ RE, the enveloping operad UR(A)<br />

is isomorphic to the operad SR(R[ · ],A) ∈ R / OE associated to A by the functor<br />

SR(R[ · ]) : RE →R / OE.<br />

Pro<strong>of</strong>. By lemma 4.1.11, the enveloping operad <strong>of</strong> an R-algebra A is realized<br />

by a reflexive coequalizer <strong>of</strong> the <strong>for</strong>m:<br />

R[S(R,A)]<br />

φs 0<br />

φd 0<br />

φd 1<br />

R[A]<br />

UR(A),<br />

where we use the notation R[X] = S(R[ · ],X). To define the morphisms<br />

φd0,φd1,φs0 we use that R[X] represents the enveloping operad <strong>of</strong> the free<br />

R-algebra A = R(X) and we apply the adjunction relation <strong>of</strong> enveloping operads<br />

(see §§4.1.8-4.1.11). But a straight<strong>for</strong>ward inspection <strong>of</strong> constructions<br />

shows that these morphisms are identified with the morphisms<br />

s0<br />

S(R[ · ], S(R,A)) d0<br />

d1<br />

S(R[ · ],A)<br />

which occur in the definition <strong>of</strong> the functor S(R[ · ],A) associated to the right<br />

R-module R[ · ]. There<strong>for</strong>e we have an identity UR(A) =SR(R[ · ],A), <strong>for</strong> every<br />

A ∈ RE. ⊓⊔<br />

10.1.4 Remark. In the point-set context, the relation UR(A) =SR(R[ · ],A)<br />

asserts that UR(A) is spanned by elements <strong>of</strong> the <strong>for</strong>m<br />

u(x1,...,xm) =p(x1,...,xm,a1,...,an),<br />

where x1,...,xm are variables and a1,...,an ∈ A, together with the relations<br />

p(x1,...,xm,a1,...,ae−1,q(ae,...,ae+s−1),ae+s,...,an+s−1)<br />

≡ p ◦m+e q(x1,...,xm,a1,...,ae−1,ae,...,ae+s−1,ae+s,...,an+s−1).<br />

Thus we recover the pointwise construction <strong>of</strong> §4.1.3.<br />

10.1.5 Functoriality <strong>of</strong> Enveloping <strong>Operads</strong>. To complete this section,<br />

we study the functoriality <strong>of</strong> enveloping operads.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!