Automorphisms of partially commutative metabelian groups

Automorphisms of a partially commutative metabelian group whose defining graph contains no cycles are studied. It is proved that an $IA$-automorphism of such a group is identical if it fixes all hanging and isolated vertices of the graph. The concepts of a factor automorphism and of a matrix automorphism are introduced. It is stated that every factor automorphism is represented as the product of an automorphism of the defining graph and a matrix automorphism.