Say there's a web application that runs on example.com, would there be a penalty for 301 redirecting the root of the domain (example.com/) to subdomain.example.com for purposes of hosting the marketing website for an application? Obviously we would expect subdomain.example.com to be what is ranked in the search engine, not example.com. We would want other paths on example.com like example.com/path/to/resource to index normally, and be unaffected by the 301 on the root path.