Classes of languages with objective-independent memory
We start from the following fact: Given a two-player game arena labelled with an alphabet , and an objective for Player 1, if is closed by subwords then if Player 1 has a winning strategy, she has one using memory . The remarkable thing is that this memory does not depend on , just on . We say that a class of languages has the if there is a function such that for all arena and , if Player 1 has a winning strategy for in then she has one using memory . This property is useful in distributed synthesis. As we saw above, the class of subword-closed languages has this property, with the factorial function. The problem is to characterise classes of languages with this property, or at least identify some non-trivial examples. A first step could be to show that for all , the class of languages recognised by automata with SCCs of size at most has this property, and identify some classes that have that property but are not subsumed by some .
