Lifting 4d dualities to 5d

In this paper we set out to further explore the connection between isolated N=2 SCFT's in four dimensions and N=1 SCFT's in five dimensions. Using 5-brane webs we are able to provide IR Lagrangian descriptions in terms of 5d gauge theories for several classes of theories including the so-called TN theories. In many of these we find multiple dual gauge theory descriptions. The connection to 4d theories is then used to lift 4d N=2 S-dualities that involve weakly-gauging isolated theories to 5d gauge theory dualities. The 5d description allows one to study the spectrum of BPS operators directly, using for example the superconformal index. This provides additional non-trivial checks of enhanced global symmetries and 4d dualities.