On expansions of weakly o-minimal non-valuational structures by convex predicates

We prove that if M = (M,≤,+, . . .) is a weakly o-minimal non-valuational structure expanding an ordered group (M,≤,+), then its expansion by a family of ‘non-valuational’ unary predicates remains non-valuational. The paper is based on the author’s earlier work on strong cell decomposition for weakly o-minimal non-valuational expansions of ordered groups.