Where does predicate collide?

An expression that, applied to one or more terms, yields a statement that is either true or false: in modern logic a predicate denotes a property (of one object) or a relation (among several), and is treated formally as a function that maps objects in a domain to a truth value. Frege's 1879 Begriffsschrift founded quantificational logic by analysing a proposition into function and argument, so that is prime or is greater than becomes a function whose value is true or false. The referent is an abstract property or relation over a domain, defined by which objects satisfy it, not the part of a sentence that grammar calls the predicate, and not an executable test written in a program.[1]

Unit

One predicate symbol of fixed arity over a domain, mapping objects or tuples to true or false

Recovery means

Not applicable

Measured by

Fixed by its extension, the set of objects or tuples that satisfy it, and evaluated as true or false under an interpretation

The part of a clause that states something about the subject, typically the verb together with its objects and complements: in the dog sleeps, the subject is the dog and the predicate is sleeps. The division of a clause into subject and predicate, and the relation of predication that joins them, has organised the study of grammar since antiquity; Rothstein's 2004 Predicates and Their Subjects works out how a predicate combines with its subject in the syntax and semantics of natural language. The referent is a constituent of a sentence in a spoken language, identified by grammar, not an abstract function to truth values and not a boolean routine in code.[2]

Unit

One clause's predicate constituent, the verb phrase said of its subject

Recovery means

Not applicable

Measured by

Identified in a parsed sentence by constituency tests and by its agreement and complementation with the subject

An expression or function that evaluates to a boolean, true or false, and is used to filter data, choose a branch, and guard whether a statement may run. Dijkstra's 1975 Guarded commands, nondeterminacy and formal derivation of programs made the predicate a guard: a boolean condition attached to a command, so the command is eligible to execute only when its predicate holds. The referent is a computable test over the state of a running program, evaluated to decide what happens next, not the abstract property or relation of logic, which need not be computable, and not the constituent of a clause that grammar calls the predicate.[3]

Unit

One boolean-valued function or condition evaluated on program state

Recovery means

Not applicable

Measured by

Evaluated at run time to true or false on given inputs, and used as a filter, a branch condition, or a guard