/// <summary> /// Gets the first adjacent vertex /// </summary> /// <param name="v">current vertex</param> /// <returns>first out-vertex</returns> /// <exception cref="ArgumentNullException"> /// <paramref name="v"/> is a null reference /// </exception> public IVertex FirstChild(IVertex v) { if (v == null) { throw new ArgumentNullException("v"); } return(Traversal.FirstTargetVertex(this.Wrapped.OutEdges(v))); }