Terminologies

lhs : Left Hand Side 

 rhs : Right Hand Side 

 p = q : an identity 

 Equational Expression : expr1 = expr2 e.g. expr1 = a*x+b and expr2 = cos[b-c] 

 copy : when an object is duplicated, byte by byte so to say, into a facsimile. 

 This definition of copy is the simplest to grasp the concept. In due places, more sophisticated definitions will be produced. 

 Structure : a structure is that which permitting Similarity to other Similars . 

 Example : Circular is a structure since it permits similarity to anything that is round . 

 Example : Red is a structure since it permits similarity to anything that is red . 

 Example : Numeral is a structure since it permits similarity to anything that is a number . 

 ff calls a list e.g. {1,2,3} as a structure , or a function e.g. cos[ ] a structure or an algebraic structure e.g. x^2-1 .