F-theory duals of M-theory on $S^1/\bbZ_2\times T^4/\bbZ_N$
  In this note, we use results of Aspinwall and Morrison to discuss the F-theory duals of certain $T^4/\bbZ_N$ orbifold compactifications of Ho\v{r}ava--Witten theory. In the M-theory limit an interesting set of rules, based on anomaly cancellation, has been developed for what gauge and matter multiplets must be present on the various orbifold fixed planes. Here we show how several aspects of these rules can be understood directly from F-theory. 
Monika Marquart, Daniel Waldram