Add functional notations for dist in parallel to equiv, namely (≡{n}≡), (≡{n}@{A}≡), (x ≡{n}≡.) and (.≡{n}≡ y).
dist
equiv
(≡{n}≡)
(≡{n}@{A}≡)
(x ≡{n}≡.)
(.≡{n}≡ y)