\set ECHO none
 remove_provenance 
-------------------
 
(1 row)

   city   |                                                                                              formula                                                                                              
----------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Berlin   | ((Susan ⊖ (Ellen ⊕ Susan ⊕ Ellen ⊕ Susan)) ⊕ (Ellen ⊖ (Ellen ⊕ Susan ⊕ Ellen ⊕ Susan)))
 New York | ((Paul ⊖ (John ⊕ Paul ⊕ John ⊕ Paul)) ⊕ (John ⊖ (John ⊕ Paul ⊕ John ⊕ Paul)))
 Paris    | ((Magdalen ⊖ (Dave ⊕ Magdalen ⊕ Nancy ⊕ Dave ⊕ Magdalen ⊕ Nancy)) ⊕ (Dave ⊖ (Dave ⊕ Magdalen ⊕ Nancy ⊕ Dave ⊕ Magdalen ⊕ Nancy)) ⊕ (Nancy ⊖ (Dave ⊕ Magdalen ⊕ Nancy ⊕ Dave ⊕ Magdalen ⊕ Nancy)))
(3 rows)