Analogous to the celebrated
Rogers-Ramanujan partition theorems, we obtain four partition theorems wherein the
minimal difference for ‘about the first half’ of the parts of a partition (arranged in
non-increasing order of magnitude) is 2. For example, we prove that the number of
partitions of n, such that the minimal difference of the ‘first half of the summands’
(that is, first [(t + 1)∕2] summands in a partition into t summands) of any partition is
2, equals the number of partitions n into summands congruent to ±1, ±2, ±5, ±6,
±8, ±9 (mod20).