An application of partition of indices to enclosings of triple systems Original Research Article

An enclosing of BIBD(v,3,λ) into BIBD(v+s,3,λ+1) is point-wise minimal if s is the smallest positive integer for which an enclosing is possible. We show that the necessary conditions are sufficient for a minimal point-enclosing of any BIBD(v,3,λ) into BIBD(v+s,3,λ+1) for 1⩽λ⩽6. Some other general results on enclosings are presented.