set/rijks_paintings/1 matches the site

public static Set Rijksmuseum_Paintings()
{
    var set = new Set()
        .WithContext()
        .WithId("https://linked.art/example/set/rijks_paintings/1")
        .WithLabel("Paintings of the Rijksmuseum")
        .WithClassifiedAs(Aat.Collection);

    set.IdentifiedBy = [new Name("Paintings of the Rijksmuseum").AsPrimaryName()];
    set.MemberOf = [
        new Set()
            .WithId("https://linked.art/example/set/rijks_objects")
            .WithLabel("Collection of the Rijksmuseum")
    ];
    set.UsedFor = [
        new Activity()
        {
            ClassifiedAs = [Aat.Curating],
            CarriedOutBy = [
                new Group()
                    .WithId("https://linked.art/example/group/rijks_paintings_dept")
                    .WithLabel("Paintings Department")
            ]
        }
    ];

    return set;
}

• Role shortcuts AsPrimaryName, AsAccessionNumber and AsSystemAssignedNumber each add a single classification, with the AAT terms Primary Name, Accession Number and System Number.

var set = new Set
{
    Context = ["https://linked.art/ns/v1/linked-art.json"],
    Id = "https://linked.art/example/set/rijks_paintings/1",
    Label = "Paintings of the Rijksmuseum",
    ClassifiedAs = [Aat.Collection],
    IdentifiedBy =
    [
        new Name("Paintings of the Rijksmuseum")
        {
            ClassifiedAs = [Aat.PrimaryName],
        },
    ],
    MemberOf =
    [
        new Set
        {
            Id = "https://linked.art/example/set/rijks_objects",
            Label = "Collection of the Rijksmuseum",
        },
    ],
    UsedFor =
    [
        new Activity
        {
            ClassifiedAs = [Aat.Curating],
            CarriedOutBy =
            [
                new Group
                {
                    Id = "https://linked.art/example/group/rijks_paintings_dept",
                    Label = "Paintings Department",
                },
            ],
        },
    ],
};

Generated from the object the example builds: every property that is set, as object initialisers, with the vocabulary constants where a term is in the registry. The fluent helpers are a convenience, not a requirement; this form and the one as written produce the same JSON.