Add to ORKGQuasicategories are simplicial sets with properties generalising those of the nerve of a category. They model weak∞-categories. Using a combinatorially defined ordinal subdivision, we examine composition rules for certain special pasting diagrams in quasicategories. The subdivision is of combinatorial interest in its own right and is linked with various combinatorial constructions. 1 Introduction. The most usual method of subdivision for a simplicial complex used in elemen-tary algebraic and geometric topology is the barycentric subdivision. There is however another very well structured subdivision construction encountered from time to time. The basic geometric construction involves chopping up
