  The relational interpretation (or RQM, for Relational Quantum Mechanics)
solves the measurement problem by considering an ontology of sparse relative
events, or "facts". Facts are realized in interactions between any two physical
systems and are relative to these systems. RQM's technical core is the
realisation that quantum transition amplitudes determine physical probabilities
only when their arguments are facts relative to the same system. The relativity
of facts can be neglected in the approximation where decoherence hides
interference, thus making facts approximately stable.
