If you have two supervisors, how do you address them? Do you write an e-mail to just one of them and forward it to the other? Do you write 'Dear A and B' and Carbon Copy (CC) it to both of them? Or do you just write to one of them and leave it up to them to do the forwarding if they feel it necessary? Also any other info on how the whole joint supervision process works would be gratefully received.

Write to the supervisor named first and cc your message to the second supervisor.

I have two supervisors and just send my emails to both of them and write Dear A and B. You could sometimes write Dear B and A so not so offend them (?!!)