Complementarities and substitutabilities in matching models

This paper describes an equilibrium matching model with two types of workers producing two different intermediate goods. Labour markets are perfectly segmented, but productive complementarities between sectors and productive substitutability within sectors arise. This deeply changes the effects of labour market policies. A welfare analysis is also conducted. Under constant returns to scale in the matching technology, the so-called Hosios condition is sufficient to guarantee the efficiency of the decentralized equilibrium.