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# minimumGrade(forFacts:)

Returns the lowest membership grade among the specified facts.

```
func minimumGrade(forFacts facts: [Any]) -> Float
```

## Parameters

`facts`

An array of objects representing truths claimed or rejected by the rule system. For details, see the [`facts`](/documentation/GameplayKit/GKRuleSystem/facts) property.

## Return Value

The lowest membership grade in the array of facts.

## Discussion

In fuzzy logic, this method is called the AND Zadeh operator, because it corresponds to the AND operator in Boolean logic.

> Note:
> If a fact is not in the ``doc://com.apple.gameplaykit/documentation/GameplayKit/GKRuleSystem/facts`` array, its membership grade for purposes of this operation is implicitly zero.

## See Also

[`facts`](/documentation/GameplayKit/GKRuleSystem/facts)

The list of facts claimed by the rule system.


---

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