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Mental Model

Every primitive in Book Duplex belongs to one of three buckets:

  1. Position
  2. Structure
  3. Flow

Everything else is a transformation or interaction of those three.

Position

Position answers where the pair is relative to equilibrium.

Position is the state of price. It does not explain whether the move is allowed to continue.

Structure

Structure answers what liquidity permits.

Structure is the terrain. It defines friction, support, resistance, and how that terrain is changing through time.

Flow

Flow answers what participants are actually doing.

Flow is commitment. It is the capital that either confirms or fails to confirm the structural picture.

The Core Compression

The whole system can be reduced to:

pressure + friction + participation
  • pressure: directional structural and flow bias
  • friction: how hard the book makes movement
  • participation: whether real traders are funding the move

How Edge Appears

Edge does not come from a single metric. It comes from either:

  • alignment
  • conflict

Alignment means the system agrees. Conflict means one layer is lying, lagging, or being overrun.

Canonical Interaction Examples

Displacement + Depth

  • stretched + thin liquidity ahead -> continuation
  • stretched + thick opposing liquidity -> rejection

Log(A/B) + Centroid

  • positive near-mid imbalance -> immediate structural support
  • positive imbalance far away -> latent support, not immediate support

Trade Profile + Depth

  • aggressive buying into thick supply -> absorption
  • aggressive buying into thin supply -> expansion

Flow vs Structure

  • agreement -> stable moves
  • conflict -> traps, adverse selection, or reversals

Full-System Read

The highest-quality continuation read looks like:

displacement positive
+ Log(A/B) positive near mid
+ centroid positive
+ trade flow positive
+ SLS gravity rising
-> continuation probability increases

The inverse uses the same logic in reverse.

Next Steps