Recursion has to do with reducing the complexity of an algorithm by analytically breaking up computational sequences into its simplest forms. Conversely, recursion also works in synthesizing components into more complex objects principally by replicating or reproducing simple component sequences over and over again. The process of breaking down a complex set of sequences into a set of simpler sequences of instructions on a computer is called reduction. The process of reduction is analogous to the process of clustering used in pattern recognition. As clustering is an aggregative concept which enables the recognition of more complex epicentric paradigms, reduction is a process of simplifying complex sequences by breaking up these long sequences into shorter simpler ones.
Reduction is a way of transforming a long hard problem into many short simple ones.
Reduction as used in studying complex problems has some strong parallels with the term clustering which is used to reduce complexity in pattern recognition. They are basically similar paradigms. The result of reducing a complicated sequence down to its simplest or optimal form leaves basic sequences which can be used as building blocks for complex systems. For example, Nature uses self-reproducing cells to build complex biological organisms. Biological, self-replicating cells are an exemplar of recursion.