Difficulty: Easy
Correct Answer: a variable or its complement
Explanation:
Introduction / Context:Precise terminology is crucial in Boolean manipulation. “Literal” is a foundational term used to count occurrences of variables in expressions and to describe canonical forms.
Given Data / Assumptions:
Concept / Approach:A literal is one appearance of a variable, either complemented or uncomplemented. For example, in A'*B*C, the literals are A', B, and C. Counting literals helps estimate implementation cost (e.g., input count to gates) and evaluate simplification results.
Step-by-Step Solution:
Step 1: Identify the unit: a single variable instance with or without complement.Step 2: Contrast with product terms (ANDed literals) and sum terms (ORed literals).Step 3: Conclude: a literal is a variable or its complement.Verification / Alternative check:Canonical SOP counts literals per product; canonical POS counts literals per sum; texts define literal exactly this way.
Why Other Options Are Wrong:
A product term: That is an AND of literals, not a literal itself.All variables in an expression: That describes the set of variables, not a literal.The inverse function: Refers to complement of the whole function, not a literal.A maxterm with all variables: That is a POS sum term, not a literal.Common Pitfalls:Confusing “literal” with “variable count” or with “term.”
Final Answer:a variable or its complement
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