Week 2 Flashcards
What do you need to define a language?
An alphabet.
Rules which govern the syntax, the ordering of the
elements.
Semantic interpretation, the assignment of meaning to
well-formed sentences
Distinguish between a sentence and a sequence of words.
Every sentence is a sequence of words but not every sequence of words is a sentence. A sentence is always grammatically correct.
What are identifiers?
Symbols for denoting propositions. E.g. A, B, C
What is the punctuation symbol for logic?
( and )
What are propositional connectives? Name them.
Elementary operators that join identifiers/propositions E.g. ¬, ^, v, => and <=>.
What are regular formulae?
Formula that use the alphabet of the given language.
Is an identifier a proposition on it’s own?
Yes.
What are well formed formulae?
A well-formed formula is a formula that uses only the alphabet of the language and obeys the grammatical rules given in the syntax of the language.
Acronym for precedence of propositional connectives.
B - Brackets
N - Negation
C - Conjunction
D - Disjunction
I - Implies
E - Equivalence
What are the semantics?
Semantics deal with the meaning of compound
propositions.
Full truth table layout for prime proposition.
T(2) T(P) T(Q) F(2)
P = T = T = F = F
Q = T = F = T = F
NP = F = F = T = T
C = T = F = F = F
D = T = T = T = F
I = T = F = T = T
E = T = F = F = T
What does -> mean in the rules of a language?
Can be (defines grammar rules (syntax) )
What do * and ? mean in terms of sentences in logic?
There is something wrong.
What are the three characteristics of a defined alphabet?
Symbols for denoting propositions.
Punctuation symbols.
Propositional Connectives
