Claims with more than one subject

How does deal with claims with more than one subject? It seems natural that
the `claim` property could also be an array, but I could not find a
reference in the specs. is this valid claim?

  {
    "@context": [
      "https://schema.org/",
      "https://w3id.org/security/v1"
    ],
     "claim": [
      {
        "id": "did:btc1:298347982739",
        "knows": {
          "id": "did:eth1:93753829747"
        }
      },
      {
        "id": "did:eth1:93753829747",
        "knows": {
          "id": "did:btc1:298347982739"
        }
      }
    ],
    "signature": {
      "type": "EcdsaKoblitzSignature2016",
      "created": "2017-12-12T11:37:12Z",
      "creator": "ecdsa-koblitz-pubkey:1LGpGhGK8whX23ZNdxrgtjKrek9rP4xWER",
      "signatureValue":
"IHRd8TlXjIwMAjO/e7jeMaa0ROHDgDrhlcXAutstXs6CXsMWJ78iwr61JZ/+LjvX9m+U1MPBNKByJvpi33/CQJo="
    }
  }