Matematiska Institutionen, Chalmers Tekniska Högskola and Göteborgs Universitet, Eklandgatan 86, S-412 96, Göteborg, Sweden
Abstract:
Recently, Babson and Steingrímsson introduced generalised permutation patterns that allow the requirement that two adjacent letters in a pattern must be adjacent in the permutation. We investigate simultaneous avoidance of two or more 3-patterns without internal dashes, that is, where the pattern corresponds to a contiguous subword in a permutation.