In Merkle DAGS doc : Merkle DAGs | IPFS Docs
I read “A Merkle DAG is a DAG where each node has an identifier, and this is the result of hashing the node’s contents — any opaque payload carried by the node and the list of identifiers of its children …”
I am trying to fully understand how a parent’s hash is created from its children. From other researches I found that the two hashes are concatenated and the result is hashed. Is it correct and if so in which order are they concatenated ?
The answer to your question is implementation specific. I just told you that in the go-merkledag implementation of MerkleDags, the hash of the root is the hash of the serialized protobuf that I linked.