Subsection title

We plot in Fig. A1 P( > xgap) for several N values. We see that, for N = 100 and xgap = 0.06, P( > 0.06) $\approx$ 20 per cent. This means that the probability of finding a gap with a size larger than six times the mean separation is not significantly small. When the mean number of lines is large, λN > > 1, our P( > xgap) approaches the result obtained by Ostriker et al. (1988) for small (but still very large if measured in units of the mean separation) xgap, i.e., P( > xgap)∼N(1 - xgap)N-1Nexp(- λxgap).