@JsonIgnore
    @Override
    @CanIgnoreReturnValue
    public TicketGrantingTicket getRoot() {
        val parent = this.getTicketGrantingTicket();
        if (parent == null) {
            return this;
        }
        return parent.getRoot();
    }
The ticket ids which are tied to this ticket.
core/cas-server-core-tickets-api/src/main/java/org/apereo/cas/ticket/TicketGrantingTicketImpl.java