The Knowledge of Preconditions principle (KoP) is proposed as a widely
applicable connection between knowledge and action in multi-agent systems.
Roughly speaking, it asserts that if some condition is a necessary condition
for performing a given action A, then knowing that this condition holds is also
a necessary condition for performing A. Since the specifications of tasks often
involve necessary conditions for actions, the KoP principle shows that such
specifications induce knowledge preconditions for the actions. Distributed
protocols or multi-agent plans that satisfy the specifications must ensure that
this knowledge be attained, and that it is detected by the agents as a
condition for action. The knowledge of preconditions principle is formalised in
the runs and systems framework, and is proven to hold in a wide class of
settings. Well-known connections between knowledge and coordinated action are
extended and shown to derive directly from the KoP principle: a "common
knowledge of preconditions" principle is established showing that common
knowledge is a necessary condition for performing simultaneous actions, and a
"nested knowledge of preconditions" principle is proven, showing that
coordinating actions to be performed in linear temporal order requires a
corresponding form of nested knowledge.Comment: In Proceedings TARK 2015, arXiv:1606.0729
