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2 edited for clarity

Hello,

I'm interested in the question, given

Given $M$ and $N$, two connected orientable manifolds of the same dimension, when is $M$#$N$ independent of the choice of orientations for M$#$N$diffeomorphic to$M$and #$N$? For instance, if \overline{N}$, where $\overline{N}$ is $N$ with the orientation reversed? If $N$ has an orientation-reversing automorphism, it that is this a necessary or sufficient condition for $M$#$N$ to be independent of the choice of orientation on diffeomorphic to $N$?

Thanks--

Zygund