I have an easy question. Could anyone answer only with yes or no? (since I would like to fill in the details myself)
Which of the following sentences are correct?
a) $\textbf{Rel}\simeq\textbf{Rel}^{op}$ b) $\textbf{Sets}\simeq\textbf{Sets}^{op}$ c) $\textbf{Pos}\simeq\textbf{Pos}^{op}$
Where Rel is the category of binary relations and Pos is the category of partially ordered sets. I think its yes, no, yes.