Practice Eliminate Useless Symbols (5.4.1.4) - Context-Free Grammars (CFG) and Languages
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Eliminate Useless Symbols

Practice - Eliminate Useless Symbols

Learning

Practice Questions

Test your understanding with targeted questions

Question 1 Easy

What is a non-generating symbol in a CFG?

💡 Hint: Think about symbols that don't lead to valid outputs.

Question 2 Easy

How can you identify unreachable symbols in a CFG?

💡 Hint: Consider whether you can reach the symbol through any rules.

4 more questions available

Interactive Quizzes

Quick quizzes to reinforce your learning

Question 1

What are non-generating symbols?

Symbols that produce terminal strings
Symbols that cannot derive terminal strings
Symbols that are reachable from the start symbol

💡 Hint: Think of what these symbols can do.

Question 2

True or False: Unreachable symbols can be derived from the start symbol.

True
False

💡 Hint: Think about how symbols connect in a CFG.

1 more question available

Challenge Problems

Push your limits with advanced challenges

Challenge 1 Hard

Given the CFG defined by productions P: A → B | C; B → D; D → E; E → ε; C → c, identify all non-generating and unreachable symbols.

💡 Hint: Trace the paths and identify the symbols that cannot lead to terminal outputs.

Challenge 2 Hard

In a CFG with S → A | B; A → a; B → C; C → ε, identify unreachable symbols and justify your choice.

💡 Hint: Evaluate the connections to the start symbol.

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Reference links

Supplementary resources to enhance your learning experience.