👉 In mathematics, a subsequence of a sequence is an ordered subset that can be derived from the original sequence by deleting some or no elements without changing the order of the remaining elements. For example, the subsequence "1, 2" is a valid subsequence of the sequence (1, 2, 3). A subsequence is also called a prefix of the original sequence. For instance, consider the sequence: 1, 2, 3, 4, and its
