{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "definitions": {
        "pets": {
            "type": "object",
            "properties": {
                "dog": {
                    "type": "array",
                    "items": {
                        "type": "string"
                    },
                    "minItems": 0
                }
            }
        }
    },
    "properties": {
        "pets": {
            "$ref": "#/definitions/pets"
        }
    },
    "required": [
        "pets"
    ]
}