2016/04/19 by Anderson, Edward
#FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc)
paper · doi:10.48550/arxiv.1604.05415
The Kuchar observables notion is shown to apply only to a limited range of theories. Relational mechanics, slightly inhomogeneous cosmology and supergravity are used as examples that require further notions of observables. A suitably general notion of A-observables is then given to cover all of these cases. `A' here stands for `algebraic substructure'; A-observables can be defined by association with each closed algebraic substructure of a theory's constraints. Both constrained algebraic structures and associated notions of A-observables form bounded lattices.