[bawolff]

> Whether you go to the park on a given day is undecidable

I feel like that is not really undecidable in the same way the halting problem is. The result does not depend on the input. It'd be like saying checking primality is undecidable if you dont know what number you're supposed to check.

[qazxcvbnm]

You're right, it's not the same. Undecidable properties are not related in general.

[bawolff]

To be more clear, i'm saying it is not undecidable in the sense that mathematicians use the term.