5.3. References and acknowledgements

Try these first

1. 1.

   What is a finite alphabet?

   Hint

   Think of common alphabets or specific collections of symbols.

2. 2.

   How many strings can be formed from a binary alphabet of {0, 1} of length 1?

   Hint

   Count each symbol in this alphabet.

3. 3.

   Is the set of all strings over a finite alphabet countable?

   • True
   • False

   Hint

   Relate this to the definition of countability.

4. 4.

   If you have an alphabet of 5 characters, how many strings of length 3 can you create?

   • 5
   • 125
   • 15

   Hint

   Apply the formula for counting strings.

5. 5.

   Show how you would create a sequence of valid strings using an alphabet of your choice. Explain your method.

   Hint

   Choose a simple alphabet to start, like {x, y, z}.

6. 6.

   Given a programming example, explain how to determine its validity based on your earlier discussions.

   Hint

   Review the definitions of valid programs discussed in class.