  FV Time is a small-scale verification project developed in the Coq proof
assistant using the Mathematical Components libraries. It is a library for
managing conversions between time formats (UTC and timestamps), as well as
commonly used functions for time arithmetic. As a library for time conversions,
its novelty is the implementation of leap seconds, which are part of the UTC
standard but usually not implemented in existing libraries. Since the verified
functions of FV Time are reasonably simple yet non-trivial, it nicely
illustrates our methodology for verifying software with Coq.
  In this paper we present a description of the project, emphasizing the main
problems faced while developing the library, as well as some general-purpose
solutions that were produced as by-products and may be used in other
verification projects. These include a refinement package between
proof-oriented MathComp numbers and computation-oriented primitive numbers from
the Coq standard library, as well as a set of tactics to automatically prove
certain decidable statements over finite ranges through brute-force
computation.
