Modal logic - satisfiability
Assuming X and Y are modal formulae and diamond X is satisfiable and diamond Y is satisfiable, how would one show that they X AND Y is satisfiable?
I don't think it requires much effort?
I think you need to choose one world and one model where X AND Y is true and that would mean it is satisfiable?
So assuming I'm going about it correctly, any ideas what model and world I should select to show this X AND Y is satisfiable?
Any advice would be great,
P.S. NO appropriate tags for this type of most, maybe someone should create a modal logic one (I can't as I'm a new user)