Function vstd::seq_lib::lemma_seq_take_update_commut1

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pub proof fn lemma_seq_take_update_commut1<A>(s: Seq<A>, i: int, v: A, n: int)

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ensures

0 <= i < n <= s.len() ==> #[trigger] s.update(i, v).take(n) =~= s.take(n).update(i, v),

If i is in the first n indices of sequence s, updating sequence s at index i with value v and then taking the first n elements is equivalent to first taking the first n elements of s and then updating index i to value v.