anchor.diff:  
   These are represented in migae as `entity-map` and `keychain`, respectively.
   
  -== [[ctors]]construction
  +== [[ctors]]constructors
   
   We have three ways to construct PersistentEntityMap objects:
   
  
positive.code: ----
  etc.  More to come.
  
  == [[keys]] Keys, keychains, keylinks, and dogtags
  
  A keylink is a namespaced keyword, e.g. `:Foo/Bar`.  A vector of
  keylinks is a keychain, which corresponds to a datastore Key, which
  
negative.code: * <<start,getting started>>
  * <<testing,testing>>
  * <<types,types>>
  * <<ctors,constructors>>
  * <<axioms,axioms>>
  * <<keys,Keys, keychains, keylinks, dogtags>>
  * <<kinds,kinds>>
  