Structural rule A famous structural rule is known as cut. Considerable effort is spent by proof theorists in showing that cut rules are superfluous in various logics. More precisely, what is shown is that cut is only (in a sense) a tool for abbreviating proofs, and does not add to the theorems that can be proved. The successful 'removal' of cut rules, known as "cut elimination", is directly related to the philosophy of "computation as normalization" (see Curry–Howard correspondence); it often gives a good indication of the complexity of deciding a given logic. Structural rule In proof theory, a structural rule is
Rule of three (writing) is often paired with quick timing, ensuring that viewers have less time to catch on to the pattern before the punch line hits. As a whole, the comedic rule of threes relies on setting up a pattern of two items and then subverting viewer expectations by breaking that pattern with the third item. One particularly notable example comes from The Dick Van Dyke Show - "Can I get you anything? Cup of coffee? Doughnut? Toupee?". Just like most comedic writing, the rule of threes in comedy relies on building tension to a comedic release. In the case of the rule