... introduced in Ichida and Fujii (1990) D Scholz, Deterministic Global Optimization: Geometric Branch -and- bound Methods and Their Applications, Springer Optimization and Its Applications 63, DOI ... (x) + (1 − λ ) · f (y) D Scholz, Deterministic Global Optimization: Geometric Branch -and- bound Methods and Their Applications, Springer Optimization and Its Applications 63, DOI 10.1007/978-1-4614-1951-8_1, ... : X → R is concave on X D Scholz, Deterministic Global Optimization: Geometric Branch -and- bound Methods and Their Applications, Springer Optimization and Its Applications 63, DOI 10.1007/978-1-4614-1951-8_3,...