What is a projection onto a set of nodes in a graph?

Question

Mathematics

Since the toaster does not allow the publication of tasks, I described the problem as best I could. There is a graph (bipartite) and it is necessary to find graphs in it for projection onto the upper set of nodes. What is a projection onto a set of nodes anyway? I can't find info anywhere.

Answer 1

A bipartite graph can be represented as a correspondence R ⊆ A×B. Then the projection of the bipartite graph onto the share A (or B) is those vertices from A (or from B) from which the edge goes.