Coordination under complementarity
Wrong scale of selection
A housing system fails when the unit of function and the unit of selection are different. The city-region must jointly provide homes, infrastructure, mobility, and access to productive locations. But local actors optimize home values, tax bases, congestion, electoral pressure, or financing needs. When these two levels diverge, demand shocks that should produce more housing get converted instead into price inflation, queues, exclusion, vacancy misallocation, or informal settlement.
The functional adaptation rate
The FAR measures how much of a demand shock is absorbed by useful coordinated capacity versus converted into pathological outputs:
A high-FAR system produces homes and infrastructure. A low-FAR system produces asset inflation, waiting lists, overcrowding, and informality.
Sheaf-like gluing
Each scale has a local section — its desired state and perceived signal. The system is coherent only when adjacent scales' sections glue into a consistent global section. Failure to glue produces a cohomology defect: a formal measure of how badly local intentions fail to compose into system-level coordination. This is analogous to how a sheaf on a topological space has well-defined global sections only when its restriction maps are compatible.
Morphogenetic hierarchy
Inspired by Michael Levin's work on bioelectric morphogenesis: lower-level cells can be recruited by higher-level tissue patterns when repair and signaling remain intact. In this simulator, the metro-scale goal pulls lower scales toward coordinated behavior through a morphogenetic term — but only when repair capacity and gluing strength are sufficient. When these break down, lower scales drift or lock in, producing the housing equivalents of developmental malformation.
Regime classification
The system can occupy four regimes. Adaptive: scales align, demand becomes capacity. Rigid lock-in: the system appears stable but vetoes prevent adaptation (NIMBY equilibrium). Chaotic drift: scales act on contradictory signals, oscillating without settling. Collapse: gluing breaks down entirely and the system cannot organize a coherent response. Basin stability measures how much shock the current regime can absorb before transitioning — a rigidly locked system in a narrow basin is paradoxically fragile.
Harm obstruction
When scales fail to glue, unabsorbed demand converts into specific harm dimensions: agency (loss of choice and access), material security (price spikes and rent burden), systemic stability (bubble fragility and tail risk), and mobility (lock-in and inability to relocate). Different coordination failures produce different harm profiles: NIMBY lock-in primarily harms agency and material security; finance misalignment primarily harms stability.
Hysteresis
The system exhibits path dependence: accumulated misallocation retroactively degrades signal fidelity. Developers misread distorted signals, municipalities misinterpret corrupted demand data, speculators amplify noise. The system's own failures distort future perception, creating a feedback loop where coordination failure breeds further coordination failure.
Model changelog
- 7-scale hierarchy (Cell through Metro) with discrete-time simulation
- 10 control parameters: demand shock, complementarity, signal fidelity, repair capacity, local veto, incumbent capture, finance misalignment, infrastructure sync, regional steering, gluing strength
- 4 presets: healthy morphogenesis, NIMBY lock-in, China-style overhang, informal urban explosion
- Sheaf-like gluing diagram with cross-scale coherence visualization
- Levin-style morphogenetic recruitment: higher scales pull lower scales toward system goals
- Metrics: coherence, FAR (functional adaptation rate), misallocation, cohomology defect, price/queue pressure
- Time-series charts for coherence, FAR, and price pressure across simulation horizon