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I’m new to formal language and searching for the solution for the following task:

$\Sigma$ is an alphabet with $\lvert \Sigma\rvert = 5$ and $k \in \mathbb{N}_0$.

I’m searching for $\lvert \Sigma^k\rvert$.

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This might help: math.stackexchange.com/questions/32247/… –  joriki Apr 11 '11 at 8:00
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$\Sigma^k$ is the set of $k$-letter words on the letters of $\Sigma$. You want to know how many of those there are. Hence @joriki's suggestion. –  lhf Apr 11 '11 at 11:58

2 Answers 2

Thank you.

$\Sigma^k$ is the set of k-letter words on the letters of Σ. You want to know how many of those there are.

So, therefor the answer is {amount_of_letters}$^5$ ?

For example: {0,1} ... 2$^5$ words possible? {a,b,c} ... 3$^5$ words possible? and so on...

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Yes. Think of a list $\Box\Box\Box\Box\Box$ and for each $\Box$ you can make $|\Sigma|$ distinct choices. So if you have $5$ boxes, there are $|\Sigma|^5$ possibilities. –  t.b. Apr 11 '11 at 12:42

proposal for solution:

k's are elements of natural number, including zero.

-> $\Sigma$'s cardinality is five. so $\Sigma^5$ = {01234} or {45678}

What I didn't understand: No word's parts are given, so how can I answer this question without knowing, what is part of the language.

What I can say is, $\Sigma^5$ has five-digit words like {abcde} or {01234}...

However, i doubt, that this is the right solution...


Best regards, jensen

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(I´m working with jensen togehter in a team) –  LaPhi Apr 11 '11 at 9:02

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