The condition of strong mixing for triangular arrays of random variables is a common condition of weak dependence. In this note, it is shown that this condition is not as general as one might believe.

The convergence rates of the sums of α-mixing (or strongly mixing) triangular arrays of heterogeneous random variables are derived. We pay particular attention to the case where central limit theorems ...

Left to right: Peng Peng, Simon Cherry and Chih-Chieh Liu from the University of California, Davis. The spatial resolution of a PET image is mainly determined by the size of the scintillation crystals ...

Figure 2: Scanning SQUID micrograph of the flux state in a section of a triangular lattice (T = 4.2 K). In the zigzag configuration, all the half-fluxons are generated in a singly connected ...