olemus
topoloogiliselt keeruline graaf (võrk)
= a graph (network) with non-trivial topological features

ülevaateid
https://en.wikipedia.org/wiki/Complex_network
https://medium.com/analytics-vidhya/introduction-to-complex-network-analysis-15b50947a794
https://www-complexnetworks.lip6.fr/~latapy/Publis/cs05.pdf