Computer science formal language

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If L concatenated with the set of all possible strings from the alphabet ∑ equals L, it indicates that L is closed under concatenation with ∑*. This means that for any string w in L, concatenating w with any sequence of symbols from ∑ results in a string that is still in L. Consequently, L must include all possible extensions of its strings using symbols from ∑. Therefore, L can be characterized as containing all strings that can be formed by concatenating its elements with any combination of symbols from ∑. This leads to the conclusion that L is likely infinite and encompasses a broad range of strings.
francisg3
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Suppose L\sum* = L for an alphabet \sum . What can we say about the possible strings in L?




I know that the \sum* is a collection of all possible words of a language and I know that 'L' is a subset of \sum* . So L concatenated with \sum* needs to be equivalent to L. I am stumped.
 
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francisg3 said:
Suppose L\sum* = L for an alphabet \sum . What can we say about the possible strings in L?

I know that the \sum* is a collection of all possible words of a language and I know that 'L' is a subset of \sum* . So L concatenated with \sum* needs to be equivalent to L. I am stumped.

How about:

If w is a word in L, than w followed by zero or more symbols from ∑ is also a word in L?
 
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