21. The binary relation a " defined by 22. There is also a primitive binary relation called order, denoted by infix " < ". 23. According to the previous lemma, we can in fact use finitely many binary relation symbols. 24. Deduction rules can then be represented by binary relations on G�del numbers of lists of formulas. 25. Then the "'independency "'induced by D is the binary relation I 26. Define on the binary relation to hold when there exists a nonzero real number such that. 27. That is why any description of set theory begins with a fundamental binary relation ". 28. The new component R is a binary relation relating values in the domain to plural variable symbols. 29. Notice that a cycle is neither necessary nor sufficient for a binary relation to be not transitive. 30. Adding a single binary relation symbol to monadic logic, however, results in an undecidable logic.
