A sequence xn is regular if ∀ n m : ℕ+, |xm − xn| ≤ m−1 + n−1.
A sequence, xn, is regular if ∀ n m : ℕ+, |xm − xn| ≤ m−1 + n−1.
Which of the above two sentences is better? Is making a variable declaration in a sentence restrictive, or nonrestrictive?