Each of the φ(i, j) edge factors (e.g., the edge between node f 3 and e 4 in Figure 1) overlaps with each of the two CRF models over one vertex (e.g., f 3 on Chinese side and e 4 on English side), and we seek agreement with the Chinese CRF model over tag assignment of f j , and similarly for e i on English side.
no direct agreement between the two CRF models is enforced, but they both need to agree with the bilingual edge factors.