Planck's law In 1880, André-Prosper-Paul Crova published a diagram of the three-dimensional appearance of the graph of the strength of thermal radiation as a function of wavelength and temperature. He determined the spectral variable by use of prisms. He analyzed the surface through what he called "isothermal" curves, sections for a single temperature, with a spectral variable on the abscissa and a power variable on the ordinate. He put smooth curves through his experimental data points. They had one peak at a spectral value characteristic for the temperature, and fell either side of it towards the horizontal axis. Such spectral sections are
Minimum rank of a graph pattern of nonzeros. The minimum rank of the graph formula_2 is denoted by formula_3 and is defined as the smallest rank of any generalized adjacency matrix of the graph. Several families of graphs may be characterized in terms of their minimum ranks. Minimum rank of a graph In mathematics, the minimum rank is a graph parameter formula_1 for any graph "G". It was motivated by the Colin de Verdière's invariant. The adjacency matrix of a given undirected graph is a symmetric matrix whose rows and columns both correspond to the vertices of the graph. Its coefficients are all 0 or