Knowledge is an iterative relational
network. Biologically, knowledge structure is a dual memory system where information is organized between two mirrored
perceptual and conceptual memories. Mathematically, we call these two memories two sets of alphabets and strings. All
of the alphabets and strings are organized iteratively as element-class relations. There exists two inverse relation-checking
functions, namely deduction and reduction. Relations can be learned and stored in between the two memories as knowledge. Relations
can also be retrieved either from perceptual to conceptual memory, or from conceptual to perceptual memory.