On Zero-Rotatable Small Graceful Trees : Caterpillars
The well-known conjecture of Ringel-Kotzig or better known graceful tree conjecture has entered to its fourth decade. As today there exits no serious attempts toward its resolution, so it is worthwhile to revisit some old concepts. In this paper we have investigated small ( i.e., trees with diameter ≤ 4) graceful trees which are caterpillars, based on the property of A graceful tree is called rotatable if it is possible to assign the smallest vertex label to an arbitrary vertex
