State resolution

[New in this version]

The room state S′(E) after an event E is defined in terms of the room state S(E) before E, and depends on whether E is a state event or a message event:

    If E is a message event, then S′(E) = S(E).
    If E is a state event, then S′(E) is S(E), except that its entry corresponding to E’s event_type and state_key is replaced by E’s event_id.

The room state S(E) before E is the resolution of the set of states {S′(E1), S′(E2), …} consisting of the states after each of E’s prev_events {E1, E2, …}, where the resolution of a set of states is given in the algorithm below.