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The bicategory of topological correspondences

It is known that a topological correspondence \((X,λ)\) from a locally compact groupoid with a Haar system \((G,α)\) to another one, \((H,β)\), produces a \(\textrm{C}^*\)-correspondence \(\mathcal{H}(X,λ)\) from \(\textrm{C}^*(G,α)\) to \(\textrm{C}^*(H,β)\). In one of our earlier article we described composition two topological correspondences. In the present article, we prove that second countable locally compact Hausdorff topological groupoids with Haar systems form a bicategory \(\mathfrak{T}\) when equipped with a topological correspondences as 1-arrows. The equivariant homeomorphisms of topological correspondences preserving the families of measures are the 2-arrows in~\(\mathfrak{T}\). One the other hand, it well-known that \(\textrm{C}^*\)-algebras form a bicateogry \(\mathfrak{C}\) with \(\textrm{C}^*\)-correspondences as 1-arrows. The 2-arrows in \(\mathfrak{C}\) are unitaries of Hilbert \(\textrm{C}^*\)-modules that intertwine the representations. In this article, we show that a topological correspondence going to a \(\textrm{C}^*\)-one is a bifunctor~\(\mathfrak{T}\to\mathfrak{C}\).