Traditionally, the main types of relations in syntax are believed to be co-ordination (parataxis) and subordination (hypotaxis). Besides this two-member opposition, there may be distinguished one more, consisting of four members, namely predicative, object, adverbial and attributive rela­tions. How these two oppositions correlate, their similarities and differences remain unclear though this question is quite essential for more adequate syntactic research.

Recently, some linguists (for example, L.Barkhudarov) extended the two-member opposition and introduced, besides co-ordination and subor­dination, the third type of relations – predicative. The new term definitely adds adequacy to research, though the term itself is hardly an apt one. The terms “co-ordination” and “subordination” do not specify elements joined from the point of view of their syntactic function, whereas the term “predicativity” does deliver the information on relations between two combining elements, i.e. subject and predicate. In other words, the term not only indicates the mutual status of the elements but also characterizes their syntactic function. Therefore, the term “predicativity” should be taken with much reserve.

It was Hjelmslev who noted that relations between two elements may be of three types: 1) both elements are relatively independent of each other (which corresponds to our term “co-ordination”); 2) the first element de­pends on the second one with the second element independent of the first (which is obviously synonymous to subordination); and, finally, 3) the first element depends on the second one and the second element, in its turn, depends on the first, which may correspond to the relation called “predica­tivity”. Hjelmslev named the third relation “interdependence”.

This term seems to be adequate and may be borrowed to fill the tertiary opposition: “co-ordination – subordination – interdependence”. The opposition of syn­tactic relations appears more homogeneous, since the terms co-ordination and subordination do not explicate syntactic functions of elements but only mark their mutual status. Since these three types of relations identify the status of elements in reference to each other, the opposition may be called “status opposition”.