different columns in the tables of the relational database), because they provide databaseindependent explanations for these dimensions.
in addition, the involved "mark-execute" mechanism for representing quantifier "all" (as illustrated by the Q, E and X 12 markers in Figure 1) is simplified to a quantification marker "✓" on the student-like edge ( Figure 2), and explained as the division operator q ✓ in relational algebra 2 : the abstract denotations and , correspond to the final results calculated by the original DCS tree according to the wide reading and narrow reading of "all", respectively.