  Several attempts have been made at constructing Abstract Meaning
Representations (AMRs) compositionally, and recently the idea of using s-graphs
with the HR-algebra (Koller, 2015) has been simplified to reduce the number of
options when parsing (Groschwitz et al., 2017). This apply-modify algebra
(AM-algebra) is a linguistically plausible graph algebra with two classes of
operations, both of rank two: the apply operation is used to combine a
predicate with its argument; the modify operation is used to modify a
predicate. While the AM-algebra correctly handles relative clauses and complex
cases of coordination, it cannot parse reflexive sentences like: "The raven
washes herself." To facilitate processing of such reflexive sentences, this
paper proposes to change the definition of s-graphs underlying the AM-algebra
to allow vertices with multiple sources, and additionally proposes an adaption
to the type system of the algebra to correctly handle such vertices.
