(Research project) Relational programming and transactions. A transaction can do an abort, which cancels the current calculation (see section 8.5). A relational program can do a fail, which says that the current calculation is wrong (see section 9.1). For this exercise, examine the relationship between abort and failure. In what cases can you give a transactional meaning to a relational program or a relational meaning to a transactional program? Can you design a computation model that combines the abilities of the transactional and relational models?