anchor.diff:  
    * It has to be a read-only query. Updating the graph as part of a predicate is not allowed.
    * It cannot end in a +RETURN+ clause, nor may it contain +UNION+
  - * If +WITH+ ends the subquery, it should be able to change the cardinality of the subquery in an for +EXISTS(...)+ interesting way.
  -In other words, they should include +WHERE+ or +SKIP+, since they could turn a query that returns rows into one that does not.
  + * If +WITH+ ends the subquery, it should be able to change the cardinality of the subquery.
  + In other words, the +WITH+ clause should include +WHERE+ or +SKIP+, since these sub-clauses can turn a query that returns rows into one that does not.
   
   ==== Simple subquery exists
  -When the subquery can be described with a single +MATCH-WHERE+ clause, the +MATCH+ keyword can be omitted.
  -The difference between this form and a simple pattern predicate, which is already available is that this form allows for introducing new variables inside the +EXISTS(...)+ scope.
  +When the subquery can be described with a single +MATCH-WHERE+ clause, the +MATCH+ keyword can be omitted, as in example 2A and B.
  +The difference between this form and a simple pattern predicate, which is already available, is that this form allows for introducing new variables inside the +EXISTS(...)+ scope.
   
   === Examples
   _Example 1A:_
   
  -Return all nodes that have a property named slogan.
  +Return all nodes that have a property named `slogan`.
   [source, cypher]
   ----
   MATCH (actor)
   WHERE EXISTS(actor.slogan)
  -RETURN actor
  -----
  -
  -_Example 1B:_
  -Return all nodes with both first name and second name:
  -[source, cypher]
  -----
  -MATCH (actor)
  -WHERE EXISTS(actor.firstName + actor.lastName)
   RETURN actor
   ----
   
  
positive.code: 
  == Proposal
  
  To make this feature more powerful, add a new function named +EXISTS+, that would exist in two forms:
  
   * Property existence checking
   * Subquery existence checking
  
negative.code: WHERE EXISTS {
  	MATCH (other:Actor)-[:ACTED_IN]->(movie)<-[:ACTED_IN]-(actor)
  	WHERE other.name = actor.name
    WITH other, count(*) as c
    WHERE c > 1
  }
  RETURN actor
  ----
  