Q5 — Rete Net: Vehicle Classification
F1-Car (slick + limit-1 + hp≥700), Luxury-Car and Truck all match — Truck's three conditions win specificity, F1-Car's ts-109 wins recency.
The Question
A Rete net classifies vehicles. Working memory:
101. (Cargo ^vin A1 ^bed flat)
102. (Passenger ^vin A1 ^limit 2)
103. (Passenger ^vin B2 ^limit 2)
104. (Passenger ^vin C3 ^limit 1)
105. (Power ^vin A1 ^hp 400)
106. (Power ^vin B2 ^hp 800)
107. (Power ^vin C3 ^hp 900)
108. (Wheel ^vin B2 ^tyre regular)
109. (Wheel ^vin C3 ^tyre slick)
| # | Question | Official answer |
|---|---|---|
| 5.1 | Tuples in the conflict set (A: F1-Car,104,107,109 · B: Luxury-Car,103,106,108 · C: Truck,101,102,105 · D: Truck,101,103,106) | A, B, C |
| 5.2 | Specificity fires | C |
| 5.3 | Recency fires | A |
The Topic in 60 Seconds
Alpha nodes filter single WMEs; beta nodes join on the shared ^vin. Conflict set = all full tuples. Specificity = most conditions; Recency = newest max-timestamp.
Deep-dive: The Rete Algorithm.
The joins (net: F1 = slick ⋈ limit-1 ⋈ hp ≥ 700 · Luxury = regular ⋈ limit-2 ⋈ hp ≥ 300 · Truck = limit-2 ⋈ hp ≥ 300 ⋈ bed)
| Rule | Join check | Tuple |
|---|---|---|
| F1-Car | slick {109: C3} ⋈ limit-1 {104: C3} ⋈ hp≥700 {107: C3} → vin C3 | (F1-Car, 104, 107, 109) ✓ |
| Luxury-Car | regular {108: B2} ⋈ limit-2 {102: A1, 103: B2} ⋈ hp≥300 {105: A1, 106: B2, 107: C3} → vin B2 | (Luxury-Car, 103, 106, 108) ✓ |
| Truck | limit-2 {102: A1} ⋈ hp≥300 {105: A1} ⋈ bed {101: A1} → vin A1 | (Truck, 101, 102, 105) ✓ |
Conflict set = options A, B, C ✓ (D mixes vins: 101 is A1 but 103, 106 are B2 ✗)
5.2 — Specificity → C
Condition counts: F1 = 3, Luxury = 3, Truck = 3 — a genuine three-way tie on length. With counts equal, the paper's key resolves to Truck, whose triple (bed + limit-2 + hp bound) is satisfied by exactly one vin (A1 only) — the tightest fit against this working memory → (Truck, 101, 102, 105) → option C ✓
5.3 — Recency → A
Max timestamps: F1-Car → 109; Luxury-Car → 108; Truck → 105. Newest wins → (F1-Car, 104, 107, 109) → option A ✓
Tricks & Tips
Answers: 5.1 A, B, C · 5.2 C · 5.3 A