anchor.diff:  
   
   [[orderability-equivalence]]
  -=== Orderability and equivalence ===
  +=== Orderability and equivalence
   
   We propose that <<orderability-def>> and <<equivalence-def>> should be aligned with each other, i.e.
   
  
positive.code: 
  
  [[equivalence-def,equivalence]]
  ==== Equivalence ====
  
  Equivalence now can be defined succinctly as being identical to equality except that:
  
  
negative.code: * `{a: expr1} = {a: expr2}` evaluates to `true` if `expr1 IS NULL AND expr2 IS NULL`
  
  
  ===== New map equality
  
  To rectify this, we propose instead to define the equality of two maps `m1` and `m2` as:
  
  