Window Classes

Every two-by-two window contains every stated digit class.

Parameters

Maths

Class: first-order.

The shared predicates define the notation and every named predicate.

(classes!="entropy" ∨ (|𝔄|>0 ∧ |𝔄| mod 3=0)) ∧ ∀r∈[0,rows-1): ∀k∈[0,cols-1): ∀j∈classIds(classes): ∃c∈window2(r,k): digitClass(classes,D(c))=j

Every 2×2 board window contains all classes named by classes at least once.

Example

---
format: open-rules
title: Window Classes example
setter: Example
source: ""
case: ""
library: https://rules.sudoku-sleuth.com/
status: read
---

```rules
sudoku 9x9
window-classes classes "parity"
```

Satisfies the rule: r1c1=1, r1c2=2, r2c1=4, r2c2=5. This two-by-two window includes both parities.

Breaks the rule: r1c1=1, r1c2=3, r2c1=5, r2c2=7. A two-by-two window contains only odd digits.