follows that . For and we have , and . If for all and then is said to be row-finite with no sources. Visualisation - Skeletons A k-graph is best visualized by drawing its 1-skeleton as a k-coloured graph where , , inherited from and defined by if and only if where are the canonical generators for . The factorisation property in for elements of degree where gives rise to relations between the edges of . C*-algebra As with graph-algebras one may associate a C*-algebra to a k-graph: Let be a row-finite k-graph with no sources then a Cuntz–Krieger family in a C*-algebra B is a collection of operators in B such that if ; are mutually orthogonal projections; if then ; for all and . is then the universal C*-algebra generated by a Cuntz–Krieger -family. References C*-algebras