In the bluemix web console, it is possible to create topics. However, is it possible to create topics using a REST API? I couldn't see documentation online - maybe I missed it.
@SHC no worries, it is easy to miss. Try here for a brief mention and link to the Swagger document for the topic administration API: https://console.ng.bluemix.net/docs/services/MessageHub/messagehub010.html#messagehub037
The docs are currently been restructured to improve discoverability. Feel free to come back if you have further questions.