Wyckoff sets (property)

{
    "$id": "https://schemas.anyterial.se/defs/v0.1/properties/spacegroups/wyckoff_sets",
    "$schema": "https://schemas.optimade.org/meta/v1.3/optimade/property_definition.json",
    "title": "Wyckoff sets",
    "x-optimade-type": "list",
    "x-optimade-definition": {
        "kind": "property",
        "version": "0.1.0",
        "format": "1.3",
        "name": "wyckoff_sets",
        "label": "wyckoff_sets_spacegroups"
    },
    "type": [
        "array",
        "null"
    ],
    "description": "Sets of Wyckoff letters related by normalizer operations.\n\nEach inner list groups Wyckoff positions that can be interchanged by the relevant normalizer action.",
    "x-optimade-unit": "inapplicable",
    "items": {
        "x-optimade-type": "list",
        "type": [
            "array",
            "null"
        ],
        "description": "One Wyckoff-set combination.",
        "items": {
            "x-optimade-type": "string",
            "type": [
                "string",
                "null"
            ],
            "description": "Wyckoff letter.",
            "x-optimade-unit": "inapplicable"
        },
        "x-optimade-unit": "inapplicable"
    },
    "examples": [
        [
            [
                "a"
            ]
        ],
        [
            [
                "i"
            ],
            [
                "h"
            ],
            [
                "g"
            ]
        ]
    ]
}