Smash Product - Adjoint Relationship

Adjoint Relationship

Adjoint functors make the analogy between the tensor product and the smash product more precise. In the category of R-modules over a commutative ring R, the tensor functor (– ⊗R A) is left adjoint to the internal Hom functor Hom(A,–) so that:

In the category of pointed spaces, the smash product plays the role of the tensor product. In particular, if A is locally compact Hausdorff then we have an adjunction

where Hom(A,Y) is the space of based continuous maps together with the compact-open topology.

In particular, taking A to be the unit circle S1, we see that the suspension functor Σ is left adjoint to the loop space functor Ω.

Read more about this topic:  Smash Product

Famous quotes containing the word relationship:

    “Henry David Thoreau, who never earned much of a living or sustained a relationship with any woman that wasn’t brotherly—who lived mostly under his parents’ roof ... who advocated one day’s work and six days “off” as the weekly round and was considered a bit of a fool in his hometown ... is probably the American writer who tells us best how to live comfortably with our most constant companion, ourselves.”
    —Edward Hoagland (b. 1932)