# Fundamentals

### Connections To The Computational Substrate

#\$defnSufficient   defn sufficient

more …about Connections To The Computational Substrate

### Negation Relations

#\$negationPreds   mutually-negating predicate (taxonomic slot) (intangible object relating predicate) (symmetric binary predicate)

### Attributes

#\$AttributeValue   attribute values (individuals)    **COMMENT NOT REVIEWED**    **GAFs NOT REVIEWED**

### Default Reasoning

#\$overrides is used when the assertions involved are general rules (axioms with quantifiers) and where those assertions will produce contradictory results in some situations. #\$overrides makes it possible to resolve the contradictions by giving one of the assertions priority over the other.

To take a trite example:

P1 = “If something is a penguin, it can’t fly.”

P2 = “If something is a bird, it can fly.”

P1 overrides P2. more …about Default Reasoning

### Expressions

#\$CycLExpression   CycL expressions

The collection of all syntactically well-formed expressions in the CycL language. This includes constants, variables, non-atomic terms, formulas, sentences, etc. Since the CycL syntax allows any CycL expression to be used as a term, #\$CycLExpression is actually coextensional with #\$CycLTerm (q.v.). Note that #\$CycLExpression, like most #\$CycLExpressionTypes, is a #\$quotedCollection (q.v.).

### Logical Connectives

#\$implies   implies    **COMMENT NOT REVIEWED**    **GAFs NOT REVIEWED**

### Entry Format

#\$arg1Format   arg 1 format

An instance of #\$ArgFormatPredicate (q.v.) used to place a particular #\$Format (q.v.) constraint on the first (or arg1 ) argument-place of a given predicate. (#\$arg1Format PRED FORMAT) means that PRED’s arg1 is constrained to FORMAT. See the reified instances #\$Format for further details.

direct instance of: #\$OpenCycDefinitionalPredicate #\$MacroRelation #\$IntangibleObjectRelatingPredicate #\$GeneralEntryFormatPredicate #\$ArgFormatBinaryPredicate

#\$arg2Format   arg 2 format more …about Entry Format

### Argument Genl

The “arg-genls” predicates are another way (besides “arg-isa”) to constrain the arguments of relations. Use of these predicates is optional and frankly not even very common. Of course, one can state more complicated sorts of constraints than “arg-isa” and “arg-genls” by asserting a longer Cyc formula, but these two types of short-cuts handle the most common cases.

#\$arg1Genl   arg 1 genl more …about Argument Genl

### Argument Type

Argument-type predicates are used to constrain the arguments of all relations, including predicates and functions. For each argument position that a relation takes, it must have an “arg-isa” for that position, even if it also has an “arg-genls” for the same position.

#\$arg1Isa   arg 1 isa more …about Argument Type

### Reifiable Functions

#\$ReifiableFunction   reifiable functions

more …

### Mathematical Functions

#\$DifferenceFn   subtraction

### Functions

#\$Function-Denotational   functions (relationships) (mathematical concepts)    **COMMENT NOT REVIEWED**    **GAFs NOT REVIEWED**

### Predicates

#\$decodingDeviceType   decoding device type    **COMMENT NOT REVIEWED**    **GAFs NOT REVIEWED**