block graphの例文

• The graphs that can be built from a single vertex by pendant vertices and true twins, without any false twin operations, are special cases of the Ptolemaic graphs and include the block graphs.
• This usage had little to do with the work of Husimi, and the more pertinent term block graph is now used for this family; however, because of this ambiguity this phrase has become less frequently used to refer to cactus graphs.
• Block graphs are examples of pseudo-median graphs : for every three vertices, either there exists a unique vertex that belongs to shortest paths between all three vertices, or there exists a unique triangle whose edges lie on these three shortest paths.
• In graph theory, a "'Ptolemaic graph "'is an undirected graph whose shortest path distances obey Ptolemy's inequality, which in turn was named after the distance-hereditary; they include the block graphs and are a subclass of the perfect graphs.