THE PHYSICS OF CONSTRAINTS IN LOW DIMENSIONAL SYSTEMS D. Schmeltzer Physics Department, City College of the City University of New York, New York 10031 ABSTRACT The wave function of the new material is characterized by the geometrical topology such as number of holes and electron-electron interactions. A possible way to investigate these properties is to formulate a Quantum theory with CONSTRAINTS. A- We report the first solution of Persistent currents for genus g=2 Aharonov-Bohm coupled rings. B- Constraints in momentum space gives rise to Non-commuting coordinate in the momentum space and can are applied to GRAPHENE. C- Phase space constraints, an application to the exclusion of double occupancy in High $T{c}$ superconductors Pseudo gap phase. The exclusion of double occupancy rise to Phase space constraints which give induces an effective interaction for holes.