It's often said that State Machine Replication and Byzantine broadcast are equivalent (e.g., the abstract of [1]), but it seems only obvious how to reduce SMR to BB. I.e., give BB one can construct an SMR by rotating the leader.
What does it even mean to reduce BB to SMR then? In SMR, there are clients and servers, but in BB there are only servers.
[1] https://drops.dagstuhl.de/opus/volltexte/2018/9796/pdf/LIPIcs-DISC-2018-7.pdf