Identifying relevant Persona or Knowledge for conversational systems is a
critical component of grounded dialogue response generation. However, each
grounding has been studied in isolation with more practical multi-context tasks
only recently introduced. We define Persona and Knowledge Dual Context
Identification as the task to identify Persona and Knowledge jointly for a
given dialogue, which could be of elevated importance in complex multi-context
Dialogue settings. We develop a novel grounding retrieval method that utilizes
all contexts of dialogue simultaneously while also requiring limited training
via zero-shot inference due to compatibility with neural Q \& A retrieval
models. We further analyze the hard-negative behavior of combining Persona and
Dialogue via our novel null-positive rank test