Quasiconcave functions over chains

We introduce order-theoretic generalized concavity. This is the study of those properties of generalized concave functions which require only that some order relations are defined on the domain and the image of the functions. In this work we define and study three classes of generalized order concave functions from chains to chains whose properties are very close to those of the family of quasiconcave functions on R. Purely order-theoretic characterization theorems are provided. © 1992 Gordon and Breach Science Publishers S.A.