ISRO CS 2023 Q.61: solution and answer

ISRO 2023 · CSQ.61 · 1 mark · MCQ

Which of the following is not a connective of First Order Logic with reference to AI (Artificial Intelligence)?

(A)
$\land$
(B)
$\lor$
(C)
<>
(D)
$\neg$

See the question in the paper

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Answer and solution

ANSWER

The symbol <> in option (c) is not a connective of First Order Logic.

Official answer: CSource: ISRO's revised and final answer key of 16 February 2024

First Order Logic builds compound sentences from atomic sentences using five standard connectives: negation $\neg$ , conjunction $\land$ , disjunction $\lor$ , implication $\Rightarrow$ and biconditional $\Leftrightarrow$ .
Option (a) $\land$ is conjunction (AND), so it is a connective.
Option (b) $\lor$ is disjunction (OR), so it is a connective.
Option (d) $\neg$ is negation (NOT), so it is a connective. It is the one unary connective; the others are binary.
Option (c) is the bare symbol <>. It is not in the list of connectives. In several programming languages it means 'not equal to', and the biconditional is written $\Leftrightarrow$ (or <=>), not <>.
So the symbol that is not a connective of First Order Logic is the one in option (c).

KEY IDEA

The connectives of First Order Logic are $\neg$ , $\land$ , $\lor$ , $\Rightarrow$ and $\Leftrightarrow$ . Any other symbol, such as <>, is not one.

WATCH OUT FOR

Reading <> as a mangled biconditional. The biconditional is $\Leftrightarrow$ (or <=>); a bare <> is the programming 'not equal' operator.

From the ISRO CS 2023 paper. Every question of this paper · The full paper (PDF, ISRO) · All 2 ISRO Logic questions, with notes