1. NEED TO GO THROUGH A FILTER.
S2[
    EDITORS[
        CITKEY(@citkey=x1){functional},
        EDNM(@editorname [KEY]=x2){functional}]]
:-
Document(Y1),Person(Y2),[Doc.Editor:Doc.Series-Editor:Doc.Translator](Y1,Y2),
Doc.key(Y1,x1),Agent.name(Y2,x2).