Three different types of transfer functions with a codomain of [0,1]. Three different types of transfer functions with a codomain of [0,1]. A global single-objective fitness value can be defined as the multiplication of several partial fitness functions based on these transfer functions. Gábor Vásárhelyi et al. Sci. Robotics 2018;3:eaat3536 Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works