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
Complement graph the one for simple graphs, since applying it to a graph with no self-loops would result in a graph with self-loops on all vertices. Several graph-theoretic concepts are related to each other via complement graphs: A self-complementary graph is a graph that is isomorphic to its own complement. Examples include the four-vertex path graph and five-vertex cycle graph. Several classes of graphs are self-complementary, in the sense that the complement of any graph in one of these classes is another graph in the same class. In the analysis of algorithms on graphs, the distinction between a graph and its complement