A concept often discussed in practical law or comparative law. "Gaps" in the law refers to situations where the actual instructions in the written law are unclear or unspecific about the actual procedure required to enforce the law in a particular circumstance.
In Abstract:
In his essay "Against the Input View of Legal Gaps", the Philosopher Tomasz Zyglewicz distinguishes between two different theories concerning legal gaps which he refers to as the "input view" and the "output view"
1. Input View: The belief that the law needs to be interpreted by Judges e.g. by drawing an analogy with another law in the civil code
2. Output View: "To say that there is a gap in the law is to draw the legislators’ attention to a deficiency in the legal text and call for its rectification by an appropriate legislative measure. Since in this picture the legal gaps are merely results of legal interpretation, I will call it the output view of legal gaps."
In Ancient Greece:
See page 4 of the "Cambridge Companion to Ancient Greek Law"