consider the following schema:

{
  "properties":{
    "a": { "type":"string"},
    "meta": {
      "type": "object",
      "properties": {
        "a": { /*what might I put here to require that obj.a == obj.meta.a?*/ }
      }
    }
  }
}

Can I require a == meta.a somehow?

Totally not required, and not even applicable to the case that led me to this question, but it’d also be interesting to know if I could do any operations, like substrings, or exponentiation (if a had been a number).