anchor.diff:      (%FIN) %i
     @>
   
  +let vectorBuildLength_exp = 
  +  <@
  +    (vectorBuild %k %FIN).Length
  +    <==>
  +    %k
  +  @>
  +
   let comAddIndex_exp = 
     <@
       %i + %j
  
positive.code: let constFold0Index_exp = 
    <@ 
      %i + 0
      <==>
      %i
    @>
  
negative.code:     %i + (%j - %k)
    @>
  
  let assocSubAddIndex_exp = 
    <@
      (%i - %j) + %k
      <==>
      %i - (%j - %k)
    @>
  
  let assocSubSubIndex_exp = 
    <@
      (%i - %j) - %k
      <==>
      %i - (%j + %k)
    @>
  
  let subSameIndex_exp = 
    <@
      %i - %i
  