Baire one star function is a term from real analysis. A function is in class Baire* one, written , and is called a Baire one star function, if for each perfect set , there is an open interval , such that is nonempty, and the restriction is continuous. The notion seems to have originated with B. Kerchheim in an article titled 'Baire one star functions' (Real Anal. Exch. 18 (1992/93), 385-399).