for L1, L2 being non empty 1-sorted
for N1 being non empty NetStr over L1
for N2 being non empty NetStr over L2 st RelStr(# the carrier of N1, the InternalRel of N1 #) = RelStr(# the carrier of N2, the InternalRel of N2 #) & the mapping of N1 = the mapping of N2 holds
for X being set st N1 is_eventually_in X holds
N2 is_eventually_in X