Steiner t-designs for large t

One of the most central and long-standing open questions in combinatorial design theory concerns the existence of Steiner t-designs for large values of t. Although in his classical 1987 paper, L. Teirlinck has shown that non-trivial t-designs exist for all values of t, no non-trivial Steiner t-design with t > 5 has been constructed until now. Understandingly, the case t = 6 has received considerable attention. There has been recent progress concerning the existence of highly symmetric Steiner 6-designs: It is shown in [M. Huber, J. Algebr. Comb. 26 (2007), pp. 453-476] that no non-trivial flag-transitive Steiner 6-design can exist. In this paper, we announce that essentially also no block-transitive Steiner 6-design can exist.Comment: 9 pages; to appear in: Mathematical Methods in Computer Science 2008, ed. by J.Calmet, W.Geiselmann, J.Mueller-Quade, Springer Lecture Notes in Computer Scienc

Moonlighting in a High Growth Economy: Evidence from U.S. State-Level Data

Despite the prevalence of multiple jobholding, there is relatively little research into its causes. Existing research has tested the predictions of standard labor models with micro data. Yet, there has been virtually no research into the relationship between moonlighting and structural differences in regional labor markets such as wages and employment growth. In this manner, this study examines the large differences in multiple jobholding rates across U.S. states. The findings indicate that multiple jobholding acts as a short-term shock absorber to cyclical changes. However, in the long-term, these effects dissipate, indicating that moonlighting plays a similar role as do changes in unemployment and labor-force participation to regional labor market shocks. Conversely, multiple jobholding rates are inversely related to average weekly earnings. Thus, job growth accompanied by real wage (and productivity) growth may result in a decline in multiple jobholding, further exacerbating potential labor shortages. Other key factors found to influence multiple jobholding include occupational structure and education. Copyright 2002 Gatton College of Business and Economics, University of Kentucky.