We address the wideband regime of additive white Gaussian noise (AWGN), as well as multipath fading, wireless networks, also denominated low SNR regime because power is shared among a large number of degrees of freedom. In this regime, the major impairment to communication is neither interference nor multipath fading, but noise, on the contrary to the high SNR regime, known to be interference-limited. First, we propose equivalent hypergraph models for the broadcast (BC) and multiple access channels (MAC) in the wideband regime, and provide a simple correspondence between these hypergraphs and the associated capacity achieving schemes. These hypergraph models, motivated by the broadcast nature of the wireless link, act as wired equivalent models for their wideband wireless counterparts. Then considering the wideband AWGN and multipath fading relay channels, we propose achievable hypergraph models constructed respectively from the capacity achieving schemes for the BC and MAC, block-Markov encoding/peaky binning, and finally common relaying strategies, and compare their respective min-cuts with the cut-set upper-bounds. Finally, we capitalize on the results for the BC, MAC and relay channels to provide achievable hypergraph models for more complex wireless networks with larger number of nodes and address multicast optimization problems. It turns out that in the wideband regime of wireless networks, network coding should remain in the digital domain, on the contrary to the high SNR regime where analog network coding performs well.