We study the expressiveness of Nested Graphs, an extension of conceptu
al graphs. Nesting is introduced as a formal version of the intuitive
''zooming in'' on descriptions of individuals. Projections are defined
inductively as the formal tool for ''reasoning with nested graphs:''
Nested graphs are translated to ''colored'' formulas. Coloring represe
nts anaphoras in a way similar to conceptual graphs. A system of Gentz
en sequents is shown to be adequate and complete with respect to proje
ctions of nested graphs.