A bar-joint framework (G,p) is the combination of a graph G and map p assigning positions, in some space, to vertices G. The rigid if every edge-length-preserving continuous motion arises from an isometry space. We will analyse rigidity when space (non-Euclidean) normed plane two designated are mapped same position. This non-genericity assumption leads us count matroid first introduced by Jacks...

Abstract. Polar stratospheric clouds (PSCs) have been observed from 2014 to 2018 the lidar observatory at Antarctic Concordia station (Dome C), included as a primary in NDACC (Network for Detection of Atmospheric Climate Change). Many these measurements performed coincidence with overpasses satellite-borne CALIOP (Cloud Aerosol Lidar Orthogonal Polarization) lidar, order perform comparison term...

It is shown that parametric down-conversion, with a short-duration pump pulse and a long nonlinear crystal that is appropriately phase matched, can produce a frequency-entangled biphoton state whose individual photons are coincident in frequency. Quantum interference experiments which distinguish this state from the familiar time-coincident biphoton state are described.