Could somebody just tell me how to write :

James is wearing a grey scarf?

in first order logic?

Thanks in advance

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- Nov 16th 2008, 06:01 AM #1

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- Nov 16th 2008, 07:28 AM #2

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Wow that seems imprecise.. That depends on how you define your properties. For instance, that could be

1) if $\displaystyle P(x)$ means "$\displaystyle x$ is james" and $\displaystyle Q(x)$ means "$\displaystyle x$ wears a grey scarf", it would be:

$\displaystyle \forall x P(x) \Rightarrow Q(x)$

2) If $\displaystyle P(x)$ means "$\displaystyle x$ is james", $\displaystyle Q(x,y)$ means "$\displaystyle x$ wears $\displaystyle y$", $\displaystyle S(x)$ means "$\displaystyle x$ is a scarf" and $\displaystyle G(x)$ means "$\displaystyle x$ is grey", then it would be

$\displaystyle \forall x P(x) \Rightarrow \exists y ( S(y) \wedge G(y) \wedge Q(x,y) )$