English to Spanish Science Mathematics & Statistics Preference analysis

I am trying to translate a technical text into Spanish, but I cannot find a translation for "double threshold order". It has not been written by a native speaker (to make things even more complicated :).
The text is about extended models of preferences (to analyze preferences of people). This paragraph is about how to take into account poor perception of preferences, that is, when it is not asolutely clear that everyone prefers A to B, but there are "intermediate situations".

"There are two main procedures to extend the existing structures to more general cases of preferences
1. Inclusion of preference relations representing (one or more) intermediate situations (usually of doubt) between strict preference and indifference. Technically, the new preference relations are represented by one or more additional binary relations (Q). In these structures, it is not possible to get a single definition of the R relation from P, Q and I. Such structures have given rise to interval orders and semi-orders and to double thresholds orders or to multiple thresholds orders."