Data structure and structural relationships “Computer programs usually operate on tables of information. In most cases these tables are not simply amorphous masses of numerical values, they involve important structural relationship between the data elements.” 
  
  Knuth, Art of Computer Programming, vol. 1 (Fundamental algorithms), 3rd edition, p. 252.


My question is what does “structural relationship between the elements” mean. How are these structures different from any mathematical structure?
Your citation is incorrect--this is on page 232 in 3rd edition, not 252 (first paragraph of &quot;Information Structures&quot;, chapter 2.1.
Based on having the chapter available, Knuth is talking about data structures in general. I agree the with suggestions above--just ignore this paragraph if it doesn't make sense or seems obvious. I personally agree that it does not seem to define anything or communicate anything clear to me.