Construction of 3-Designs Using (1,\sigma)-Resolution
  The paper deals with recursive constructions for simple 3-designs based on other 3-designs having $(1, \sigma)$-resolution. The concept of $(1, \sigma)$-resolution may be viewed as a generalization of the parallelism for designs. We show the constructions and their applications to produce many previously unknown infinite families of simple 3-designs.   We also include a discussion of $(1,\sigma)$-resolvability of the constructed designs. 
Trung Van Tran
math.CO