Example: Examples of Strings over Alphabets

(related to Definition: Strings (words) over an Alphabet)

Example 1

Let $\Sigma:=\{a,b,c\}$ be our alphabet. Then

$a,$ $aa$, $aaaa$, $bca$, $acc$, $aabbcc$, $bbbaaa$,

are possible strings in $\Sigma^*$.

Example 2

Let $\Sigma$ be the set of all Capital and lowercase Latin letters, including the empty space, the comma, the point, the question mark, and the exclamation mark. Then $\Sigma^*$ consists of (infinitely many) sentences, which can be written using the Latin letters, some of them making sense like

"Socrates is a man."

some of which without any sense like

"DLdfa hidb!zw. alsei?"

Example 3

Let $\Sigma:=\{0,1,2,3,4,5,6,7,8,9,+,=\}$. Then these are examples of possible strings over this alphabet:

$1=1$, $1=0$, $1+1=2$ $=32$ $===$ $30014$ $2222=333=+++$

Examples: 1

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  1. Knauer Ulrich: "Diskrete Strukturen - kurz gefasst", Spektrum Akademischer Verlag, 2001