있어서

In a sentence

• 여기에 문제가 있어서 해결이 필요합니다.

  There is a problem here, so a solution is needed.

  Here, '있어서' indicates the existence ('있다') of an issue and connects it to the need for a solution, showing causality between the existence of a problem and the following statement.

• 그는 동아리에 관심이 있어서 가입했어요.

  He had an interest in the club, so he joined.

  Here, '있어서' is used to link the possession of interest ('있다') with the action of joining, indicating a reason.

• 회의가 늦게 끝나서 아직 사무실에 남아 있을 수 있어서 다행이에요.

  Fortunately, they could still remain in the office because the meeting ended late.

  In this sentence, '있어서' relates to the state of being able to remain ('있다') due to a preceding condition ('end of a meeting'), illustrating a temporal cause-and-effect relationship.