Suborthogonal double cover

Suborthogonal double cover --- субортогональное двойное покрытие.

A suborthogonal double cover (or SODC) of [math]\displaystyle{ K_{n} }[/math] by a simple graph [math]\displaystyle{ G }[/math] is a set [math]\displaystyle{ S = (G_{1}, \ldots, G_{s}) }[/math] of subgraphs of [math]\displaystyle{ K_{n} }[/math], called pages, isomorphic to [math]\displaystyle{ G }[/math] such that

• every edge of [math]\displaystyle{ K_{n} }[/math] is contained in exactly two pages,
• [math]\displaystyle{ |E(G_{i}) \cap E(G_{j})| \leq1, \; \forall i \neq j }[/math], i.e. two different pages have at most one edge in common.

An SODC differs from an ODC in the second condition, where for ODCs the edge sets of different pages are required to have exactly one edge in common.