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@ -23,21 +23,21 @@ The state resolution algorithm for version 2 rooms uses the following
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definitions, given the set of room states
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{*S*<sub>1</sub>, *S*<sub>2</sub>, …}:
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Power events
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**Power events.**
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A *power event* is a state event with type `m.room.power_levels` or
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`m.room.join_rules`, or a state event with type `m.room.member` where
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the `membership` is `leave` or `ban` and the `sender` does not match the
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`state_key`. The idea behind this is that power events are events that
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might remove someone's ability to do something in the room.
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Unconflicted state map and conflicted state set
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**Unconflicted state map and conflicted state set.**
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The *unconflicted state map* is the state where the value of each key
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exists and is the same in each state *S*<sub>*i*</sub>. The *conflicted
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state set* is the set of all other state events. Note that the
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unconflicted state map only has one event per `(event_type, state_key)`,
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whereas the conflicted state set may have multiple events.
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Auth difference
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**Auth difference.**
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The *auth difference* is calculated by first calculating the full auth
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chain for each state *S*<sub>*i*</sub>, that is the union of the auth
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chains for each event in *S*<sub>*i*</sub>, and then taking every event
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@ -45,11 +45,11 @@ that doesn't appear in every auth chain. If *C*<sub>*i*</sub> is the
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full auth chain of *S*<sub>*i*</sub>, then the auth difference is
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∪ *C*<sub>*i*</sub> − ∩ *C*<sub>*i*</sub>.
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Full conflicted set
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**Full conflicted set.**
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The *full conflicted set* is the union of the conflicted state set and
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the auth difference.
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Reverse topological power ordering
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**Reverse topological power ordering.**
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The *reverse topological power ordering* of a set of events is the
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lexicographically smallest topological ordering based on the DAG formed
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by auth events. The reverse topological power ordering is ordered from
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@ -71,7 +71,7 @@ events using Kahn's algorithm for topological sorting, and at each step
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selecting, among all the candidate vertices, the smallest vertex using
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the above comparison relation.
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Mainline ordering
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**Mainline ordering.**
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Given an `m.room.power_levels` event *P*, the *mainline of* *P* is the
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list of events generated by starting with *P* and recursively taking the
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`m.room.power_levels` events from the `auth_events`, ordered such that
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@ -96,7 +96,7 @@ events: for events *x* and *y*, *x* < *y* if
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same `origin_server_ts`, but *x*'s `event_id` is *less* than *y*'s
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`event_id`.
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Iterative auth checks
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**Iterative auth checks.**
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The *iterative auth checks algorithm* takes as input an initial room
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state and a sorted list of state events, and constructs a new room state
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by iterating through the event list and applying the state event to the
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