Galactic chemical evolution and nucleocosmo chronology: Analytic quadratic models

This paper studies models of the chemical evolution of the Galaxy for a star formation rate proportional to the square of the mass of gas. The first objective is to find analytic solutions to the gas mass and star mass for time-dependent rates of gaseous infall onto the disk. The second objective is to compare these quadratic models to models having linear star formation rates. I do this by comparing m(t), S(t), Z(t), S(<Z), and r(235U)/r(238U) for comparison models that have the same initial disk mass, the same infall rate, and the same final gas fraction