We denote the k-th path between i-th question concept c (q) i ∈ C q and j-th answer concept c (a) j ∈ C a as P i,j [k], which is a sequence of triples: Note that the relations are represented with trainable relation vectors (initialized with pretrained relation embeddings), and concept vectors are the GCNs' outputs (h (l) ).
each triple can be represented by the concatenation of the three corresponding vectors.