  A k-gap is a finite k-sequence of pairwise disjoint monotone families of
infinite subsets of N mixed in such a way that we cannot find a partition of N
such that each family is trival on one piece of the partition. We prove that,
relative to the comparison given by restriction to infinite subsets of N, for
every positive integer k there is a finite basis for the class of all analytic
k-gaps . We also build the fine structure theory of analytic k-gaps and give
some applications.
  The content of Chapter 1 of this manuscript have been published as:
  A. Avil\'es, S. Todorcevic, Finite basis for analytic multiple gaps, Publ.
Math. IHES. 121 (2015), 57-79.
  The content of Chapter 2 (except some technical results from 2.5 and 2.6) and
Section 3.1, largely revised and improved, has ben published as:
  A. Avil\'es, S. Todorcevic, Types in the n-adic tree and minimal analytic
gaps, Adv. Math. 292 (2016), 558-600.
  The content of Sections 3.4, 4.1 and 4.3 have been published as:
  A. Avil\'es, S. Todorcevic, Isolating subgaps of a multiple gap, Monatsh.
Math. 186 (2018), 373--392.
  The rest of contents may appear elsewhere.
