The maxhi schema is described in Wiki World, Consumerium and the Know-How Wiki.
It is a simple "language" for modeling preferences and priorities for the purpose of MultiObjectiveOptimization.
Essentially, "maxhi" is short for "maximize with high priority." Corresponding logisms include "maxlo," "minhi" and "minlo." A fifth designator, "nullo," indicates neutrality, which means a parameter can be ignored when making the decision being modeled.
In this nomenclature, one of these five designators is called a "norm." A list of variables designated by norms is called a "NormSpec," or normative specification. Except for "nullo," a norm has two parts, a preference (or signum) of "max" or "min" and a priority "hi" or "lo."
The combination of signa (plural of signum) assigned to (say) n parameters reveals which of the 2n efficient frontiers is considered efficient by the respondent. The combination of priorities identifies which region on the efficient frontier represents preferred biases in negotiating tradeoffs.
This can be illustrated precisely (at least for small data sets) using my program at http://geocities.com/n8chz/dom.txt