Cactus Language • Semantics 3
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https://inquiryintoinquiry.com/2025/10/10/cactus-language-semantics-3/
The task before us is to specify a “semantic function” for
the cactus language ‡L‡ = ‡C‡(‡P‡), in other words, to define
a mapping from the space of syntactic expressions to a space of
logical statements which “interprets” each expression of ‡C‡(‡P‡)
as an expression which says something, an expression which bears
a meaning, in short, an expression which denotes a proposition,
and is in the end a sign of an indicator function.
When the syntactic expressions of a formal language are given
a referent significance in logical terms, for example, as denoting
propositions or indicator functions, then each form of syntactic
combination takes on a corresponding form of logical significance.
A handy way of providing a logical interpretation for the expressions of
any given cactus language is to introduce a family of operators on indicator
functions called “propositional connectives”, to be distinguished from the
associated family of syntactic combinations called “sentential connectives”,
where the relationship between the two realms of connection is exactly that
between objects on the one hand and their signs on the other.
A propositional connective, as an entity of a well‑defined functional and
operational type, can be treated in every way as a logical or mathematical
object and thus as the type of object which can be denoted by the corresponding
form of syntactic entity, namely, the sentential connective appropriate to the
case at hand.
There are two basic types of connectives, called the “blank connectives”
and the “bound connectives”, respectively, with one connective of each type
for each natural number k = 0, 1, 2, 3, … .
Blank Connective —
• The “blank connective” of k places is signified by the concatenation
of the k sentences filling those places.
• For the initial case k = 0, the blank connective is an empty string or
a blank symbol, both of which have the same denotation among propositions.
• For the generic case k > 0, the blank connective takes the form s₁ ⋅ … ⋅ sₖ.
In the type of data called a “text”, the use of the center dot “⋅” is generally
supplanted by whatever number of spaces and line breaks serve to improve the
readability of the resulting text.
Bound Connective —
• The “bound connective” of k places is signified by the surcatenation
of the k sentences filling those places.
• For the initial case k = 0, the bound connective is an empty closure,
an expression taking one of the forms (), ( ), ( ), … with any number
of spaces between the parentheses, all of which have the same denotation
among propositions.
• For the generic case k > 0, the bound connective takes the form (s₁ , … , sₖ).
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https://www.researchgate.net/post/Cactus_Language_Semantics