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
Strength of a graph Strength of a graph In the branch of mathematics called graph theory, the strength of an undirected graph corresponds to the minimum ratio "edges removed"/"components created" in a decomposition of the graph in question. It is a method to compute partitions of the set of vertices and detect zones of high concentration of edges, and is analogous to graph toughness which is defined similarly for vertex removal. The strength formula_1 of an undirected simple graph "G" = ("V", "E") admits the three following definitions: Computing the strength of a graph can be done in polynomial time, and the first such