Formal Verification · All levels

Formal Coverage & Signoff

How to build credible formal signoff through proof-quality metrics, cone-of-influence-aware coverage interpretation, reachability using cover properties, bounded-proof limits, and integrated closure with simulation-based verification evidence.

Section goal

How to study this section

Start with each topic hub and restate the requirement intent in your own words.
Use reports and debug pages to classify first divergence accurately.
Practice worked examples and interview drills with fixed run metadata.
Close with checklist and residual-risk framing before signoff claims.

Topics

formal-coverage-metrics/ - Formal Coverage Metrics: Beyond Green Proof Counts
cover-properties/ - Cover Properties and Reachability Confidence
bounded-proof-signoff/ - Bounded Proof Signoff: What a Depth Actually Proves
formal-signoff-criteria/ - Formal Signoff Criteria and Integration with Simulation Coverage

Formal deep dive

Signoff quality is requirement-centric and must integrate proof status, reachability, bounded limits, and waiver governance.

Concept diagram

diagram

FORMAL SIGNOFF PYRAMID

requirements -> properties and covers -> quality metrics -> waiver governance -> release decision

Metric graph

diagram

SIGNOFF CONFIDENCE TREND

fully proven critical    ███████
bounded-only critical    ████
unexplained cover gaps   ███

Metrics and artifacts to collect

requirement-to-proof closure map
critical cover reachability and gap aging
bounded-only risk register
waiver debt with owner and expiry

Mini case study

A release review blocked signoff until bounded-only properties were paired with explicit residual-risk and replay plans.

Debug branches

Separate status color from proof quality dimensions.
Treat unreachable critical covers as signoff blockers.
Document bounded-horizon rationale with architecture limits.

Senior review question

Ask: which requirement intent is proven, under which assumptions, and what residual risk remains?

Practice this lesson

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