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I realize most people work in "convenient categories" where this is not an issue.

In most topology books there is a proof of the fact that there is a natural homeomorphism of function spaces (with the compact-open topology): $F(X\times Y,Z)\cong F(X,F(Y,Z))$ when $X$ is Hausdorff and $Y$ is locally compact Hausdorff. There is also supposed to be a homeomorphism in the based case with the same conditions on $X$ and $Y$: $F_{\ast}(X\wedge Y,Z)\cong F_{\ast}(X,F_{\ast}(Y,Z))$involving spaces of based maps and the smash product $\wedge$. This, for instance, is asserted on n-lab. I checked the references listed on this page and many other texts but have not found a proof of this "well-known fact."

It seems pretty clear if $X$ and $Y$ are compact Hausdorff (EDIT: in fact this is Theorem 6.2.38 of Maunder's Algebraic Topology) but can this really be proven in this generality?

Can anyone provide a reference for a proof?

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    Showing the desired isomorphism is a homeomorphism should require you make use of compact sets in the quotient space $X\wedge Y$. This is non-obvious to me. Are you sure the space $F_{\ast}(X\wedge Y,Z)$ is homeomorphic to the relative mapping space $F((X\times Y,X\vee Y),(Z,z_0))$?2011-02-05

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I'm pretty sure that this result is proved in the book of Maunder and it must be somewhere between proposition 6.2.37 and theorem 6.3.4, pages 221-222, that unfortunately Google doesn't show right now.

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    I checked this out. Prop. 6.2.37 and 6.2.38 say: $F_{\ast}(X\wedge Y,Z)\rightarrow F_{\ast}(X,F_{\ast}(Y,Z))$ is 1-1, continuous if $X$ is Hausdorff, onto if $Y$ is locally compact Hausdorff, and a homeomorphism if $X$ and $Y$ are **compact Hausdorff**. So you have a continuous bijection as Arturo points out, but I am not yet convinced.2011-02-05
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There is a nice exposition: Strickland's Category of CGWH spaces (see Prop. 2.12 and 5.7).

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    Thanks for this link. I am well aware of these situations in categories like CGWH but I am asking strictly about the compact-open topology (which is not the case in these notes). The mapping spaces here are as usual some left adjoint functor applied to the compact-open mapping space. I do not ask this question for practical reasons. It seems well-documented that categories like CG and CGWH are going to be practical for many situations. I ask because people seem to think it is true and I've never been given good reason to believe it.2011-09-06