  In this work we study the large-scale structure around a sample of non-fossil
systems and compare the results with earlier findings for a sample of genuine
fossil systems selected using their magnitude gap. We compute the distance from
each system to the closest filament and intersection as obtained from a
catalogue of galaxies in the redshift range $0.05 \le z \le 0.7$. We then
estimate the average distances and distributions of cumulative distances to
filaments and intersections for different bins of magnitude gap. We find that
the average distance to filaments is $(3.0\pm 0.8)$ $R_{200}$ for fossil
systems, whereas it is $(1.1\pm 0.1)\,R_{200}$ for non-fossil systems.
Similarly, the average distance to intersections is larger in fossil than in
non-fossil systems, with values of $(16.3\pm 3.2)$ and $(8.9\pm 1.1)
\,R_{200}$, respectively. Moreover, the cumulative distributions of distances
to intersections are statistically different between fossil and non-fossil
systems. Fossil systems selected using the magnitude gap appear to be, on
average, more isolated from the cosmic web than non-fossil systems. No
dependence is found on the magnitude gap (i.e. non-fossil systems behave in a
similar manner independently of their magnitude gap and only fossils are found
at larger average distances from the cosmic web). This result supports a
formation scenario for fossil systems in which the lack of infalling galaxies
from the cosmic web, due to their peculiar position, favours the building of
the magnitude gap via the merging of all the massive satellites with the
central galaxy. Comparison with numerical simulations suggests that fossil
systems selected using the magnitude gap are not old fossils of the ancient
Universe, but systems located in regions of the cosmic web not influenced by
the presence of intersections.
