Four teams can each have a plausible scope register and still disagree about the same work. Explore the fictional Pennine Viaduct Renewal Programme: inspect the interface rules, resolve a drainage dispute, and see what still prevents a coherent global view.
Interactive teaching example · fictional UK infrastructure programme. Choices change this page only and reset on reload; no project record, approval or file is created. Start with the problem, inspect a rule in the checker, then compare the resolved examples.
The Pennine Viaduct Renewal Programme has four major work packages. Each package maintains its own scope register. Explore each package — then run the conflict detector to see what lurks in the overlaps.
Sheaf theory offers rigorous language for asking whether local data can compose into a consistent global picture. This page implements a finite comparison on declared interfaces; it does not prove that a complete project sheaf has been constructed.
Use a graph of work packages and shared interfaces: physical space, deliverables or resources. The comparison maps run from each package to its interface; the line between two packages does not imply one controls the other.
This toy makes interfaces first-class so that contradictions can be located rather than left dispersed across package records.
Each work package carries local data: its own view of scope items, quantities, cost, and responsibility. This is the "local section" over that node.
Here, “local sections” are the package facts declared for the overlapping zone. Their independent truth is not established by the checker.
For each edge (interface), a restriction map projects each work package's local data down to the shared interface zone.
The comparison rule requires the projected values to be equal or compatible within a declared tolerance. If not → a located incoherence.
Collect the four local accounts into one tuple. This finite model calls that tuple a compatible candidate only when all six selected interface rules pass. A missing value keeps the result undecided.
If gluing fails, these selected accounts cannot form one coherent view until the mismatch is investigated. Other unmodelled project facts remain outside the result.
Keep the whole package register locally. For the drainage overlap, extract just the field installation owner. WP1 says WP1; WP2 says WP2. Those values fail the same-owner rule. The £420k and £380k estimates explain why the dispute matters, but unequal estimates alone do not establish duplicate scope.
The containment rule asks a different question: is the provided width at least the required width? The symbol ~e means the declared rule for that interface. Inequalities and missing-data states here are an applied compatibility model; they are not a proof of the existence or uniqueness axioms of a sheaf.
The cover is a choice. These four packages and six overlaps leave out other suppliers, time periods and constraints. Green means this declared slice agrees. It cannot establish completeness, engineering adequacy or whole-project approval.
Select a work package, then an interface to inspect the two projected values and their comparison rule. Green = passes the selected rule. Amber = information missing. Red = fails the selected rule.
Choose a work package from the list to inspect its interfaces and consistency status.
Walk through an illustrative drainage decision. Advancing the example changes the declared owner in this browser and rechecks the interfaces. Resolving one dispute does not resolve every overlap.
Original accounts. No simulated ownership decision has been applied.
Explicit overlap rules could add a repeatable compatibility check to PMO review. Whether that improves detection, cost or schedule outcomes is an empirical question, not a result of this prototype.
Infrastructure programmes often distribute scope across packages, contracts, models and authorities. That makes their interfaces a plausible place to test explicit compatibility rules—but neither contract form nor gate process guarantees that the chosen cover is useful.
Federated models and interface registers may supply structured local facts. A useful checker would still need carefully governed mappings, units, tolerances and authority—not merely an automated graph conversion.