code: private PairSet<T, I> createFromIndices(BinaryMatrix bm) {
  		return new PairSet<T, I>(bm, allTransactions, allItems);
  	}
docs: A shortcut for <code>new PairSet&lt;T, I&gt;(matrix, mapping)</code>
  
  @param bm
  {@link BinaryMatrix} instance to link
  @return the new {@link PairSet} with the given {@link BinaryMatrix}
  instance and the same mapping of this