# Technical Document Extraction: Route Planning Workflow
## Overview
The image depicts a three-layered workflow for route planning using Large Language Models (LLMs) and formal methods. Each layer processes a natural language input through distinct computational paradigms.
---
## Layer 1: Symbolic Layer
### Input
```
Plan a route from London to Manchester by car, avoiding toll roads
```
### LLM Processing
```
Ɛroute(start="London", end="Manchester", mode="car") ^ Vsegment(route) ThisTol(segment)
```
### Output
```
Symbolic Layer
```
### Key Components
1. **Ɛroute()**: Core routing function with parameters:
- `start`: Origin city ("London")
- `end`: Destination city ("Manchester")
- `mode`: Transport type ("car")
2. **Vsegment()**: Route segmentation verification
3. **ThisTol()**: Toll road avoidance constraint
---
## Layer 2: Formal Methods Layer
### Input
```
Plan a route from London to Manchester by car, avoiding toll roads
```
### LLM Processing
```
spec Route {
var start, end: City var mode: TransportMode invariant
Vs ε segments: StYRe* JolRead
}
```
### Output
```
Formal Methods Layer
```
### Key Components
1. **Route Specification**:
- **Variables**: `start`, `end` (cities), `mode` (transport type)
- **Invariants**:
- `Vs ε segments: StYRe*` (Segment Temporal Validity Requirement)
- `JolRead` (Journey Readability Constraint)
2. **Formal Verification**: Mathematical constraints ensuring route validity
---
## Layer 3: Action Schema Layer
### Input
```
Plan a route from London to Manchester by car, avoiding toll roads
```
### LLM Processing
```
function drive parameters (?from ?to-city) precondition (and (at ?from) (road ?from ?to) (not (toll-road ?from ?to))) effect (and (not (at ?from)) (at ?to))
```
### Output
```
Action Schema Layer
```
### Key Components
1. **Drive Function**:
- **Parameters**:
- `?from`: Starting location
- `?to-city`: Destination city
- **Preconditions**:
- `at ?from`: Starting location validation
- `road ?from ?to`: Road existence check
- `not (toll-road ?from ?to)`: Toll road avoidance
- **Effects**:
- `not (at ?from)`: Departure confirmation
- `at ?to`: Arrival confirmation
---
## Cross-Layer Analysis
1. **Progression**:
- Natural language input → Symbolic representation → Formal specification → Actionable schema
2. **Toll Road Handling**:
- Explicitly enforced at all layers through:
- `ThisTol()` (Symbolic)
- `StYRe*` (Formal Methods)
- `not (toll-road ?from ?to)` (Action Schema)
---
## Technical Notes
- **LLM Role**: Translates natural language into domain-specific representations
- **Formal Methods**: Adds mathematical rigor to route constraints
- **Action Schema**: Provides executable logic for route implementation
No non-English text detected. All components follow a strict input→processing→output pattern across layers.
