DMGT

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https://doi.org/10.7151/dmgt

Discussiones Mathematicae Graph Theory

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Discussiones Mathematicae Graph Theory

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Discussiones Mathematicae Graph Theory 24(3) (2004) 509-527
DOI: https://doi.org/10.7151/dmgt.1249

DIFFERENCE LABELLING OF DIGRAPHS

Martin Sonntag

Faculty of Mathematics and Computer Science
TU Bergakademie Freiberg
Agricola-Str. 1, D-09596 Freiberg, Germany

e-mail: M.Sonntag@math.tu-freiberg.de

Abstract

A digraph G is a difference digraph iff there exists an S ⊂ N+ such that G is isomorphic to the digraph DD(S) = (V,A), where V = S and A = {(i,j):i,j ∈ V∧i−j ∈ V}.

For some classes of digraphs, e.g. alternating trees, oriented cycles, tournaments etc., it is known, under which conditions these digraphs are difference digraphs (cf. [5]). We generalize the so-called source-join (a construction principle to obtain a new difference digraph from two given ones (cf. [5])) and construct a difference labelling for the source-join of an even number of difference digraphs.

As an application we obtain a sufficient condition guaranteeing that certain (non-alternating) trees are difference digraphs.

Keywords: graph labelling, difference digraph, oriented tree.

2000 Mathematics Subject Classification: 05C78, 05C20.

References

[1] D. Bergstrand, F. Harary, K. Hodges, G. Jennings, L. Kuklinski and J. Wiener, The sum number of a complete graph, Bull. Malaysian Math. Soc. (Second Series) 12 (1989) 25-28.
[2] D. Bergstrand, F. Harary, K. Hodges, G. Jennings, L. Kuklinski and J. Wiener, Product graphs are sum graphs, Math. Mag. 65 (1992) 262-264, doi: 10.2307/2691455.
[3] G.S. Bloom and S.A. Burr, On autographs which are complements of graphs of low degree, Caribbean J. Math. 3 (1984) 17-28.
[4] G.S. Bloom, P. Hell and H. Taylor, Collecting autographs: n-node graphs that have n-integer signatures, Annals N.Y. Acad. Sci. 319 (1979) 93-102, doi: 10.1111/j.1749-6632.1979.tb32778.x.
[5] R.B. Eggleton and S.V. Gervacio, Some properties of difference graphs, Ars Combin. 19A (1985) 113-128.
[6] M.N. Ellingham, Sum graphs from trees, Ars Combin. 35 (1993) 335-349.
[7] S.V. Gervacio, Which wheels are proper autographs?, Sea Bull. Math. 7 (1983) 41-50.
[8] S.V. Gervacio, Difference graphs, in: Proc. of the Second Franco-Southeast Asian Math. Conf., Univ. of the Philippines, May 17-June 5, 1982.
[9] R.J. Gould and V. Rödl, Bounds on the number of isolated vertices in sum graphs, in: Y. Alavi, G. Chartrand, O.R. Ollermann and A.J. Schwenk, ed., Graph Theory, Combinatorics, and Applications 1 (Wiley-Intersci. Publ., Wiley, New York, 1991) 553-562.
[10] T. Hao, On sum graphs, J. Combin. Math. and Combin. Computing 6 (1989) 207-212.
[11] F. Harary, Sum graphs and difference graphs, Congress. Numer. 72 (1990) 101-108.
[12] F. Harary, Sum graphs over all the integers, Discrete Math. 124 (1994) 99-105, doi: 10.1016/0012-365X(92)00054-U.
[13] F. Harary, I.R. Hentzel and D.P. Jacobs, Digitizing sum graphs over the reals, Caribb. J. Math. Comput. Sci. 1, 1 & 2 (1991) 1-4.
[14] N. Hartsfield and W.F. Smyth, The sum number of complete bipartite graphs, in: R. Rees, ed., Graphs and Matrices (Marcel Dekker, New York, 1992) 205-211.
[15] N. Hartsfield and W.F. Smyth, A family of sparse graphs of large sum number, Discrete Math. 141 (1995) 163-171, doi: 10.1016/0012-365X(93)E0196-B.
[16] M. Miller, J. Ryan and W.F. Smyth, The sum number of the cocktail party graph, Bull. Inst. Comb. Appl. 22 (1998) 79-90.
[17] M. Miller, Slamin, J. Ryan and W.F. Smyth, Labelling wheels for minimum sum number, J. Combin. Math. and Combin. Comput. 28 (1998) 289-297.
[18] W.F. Smyth, Sum graphs of small sum number, Coll. Math. Soc. János Bolyai, 60. Sets, Graphs and Numbers, Budapest (1991) 669-678.
[19] W.F. Smyth, Sum graphs: new results, new problems, Bulletin of the ICA 2 (1991) 79-81.
[20] W.F. Smyth, Addendum to: ``Sum graphs: new results, new problems'', Bulletin of the ICA 3 (1991) 30.
[21] M. Sonntag, Difference labelling of cacti, Discuss. Math. Graph Theory 23 (2003) 55-65, doi: 10.7151/dmgt.1185.
[22] M. Sonntag, Difference labelling of the generalized source-join of digraphs, Preprint Series of TU Bergakademie Freiberg, Faculty of Mathematics and Computer Science, Preprint 2003-03 (2003) 1-18, ISSN 1433-9307.
[23] M. Sonntag and H.-M. Teichert, Sum numbers of hypertrees, Discrete Math. 214 (2000) 285-290, doi: 10.1016/S0012-365X(99)00307-6.
[24] M. Sonntag and H.-M. Teichert, On the sum number and integral sum number of hypertrees and complete hypergraphs, Discrete Math. 236 (2001) 339-349, doi: 10.1016/S0012-365X(00)00452-0.
[25] H.-M. Teichert, The sum number of d-partite complete hypergraphs, Discuss. Math. Graph Theory 19 (1999) 79-91, doi: 10.7151/dmgt.1087.
[26] H.-M. Teichert, Classes of hypergraphs with sum number 1, Discuss. Math. Graph Theory 20 (2000) 93-104, doi: 10.7151/dmgt.1109.
[27] H.-M. Teichert, Sum labellings of cycle hypergraphs, Discuss. Math. Graph Theory 20 (2000) 255-265, doi: 10.7151/dmgt.1124.
[28] H.-M. Teichert, Summenzahlen und Strukturuntersuchungen von Hypergraphen (Berichte aus der Mathematik, Shaker Verlag Aachen, 2001).

Received 21 July 2003
Revised 24 February 2004


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