User blog comment:P進大好きbot/New Googological Ruler/@comment-39605890-20191208005500

Slight nitpick

> The truth predicate itself is a Σk-formula, and hence it is very difficult to explicitly write down the formula for the case k>100.

You need to go a little higher in the Levy hierarchy to define it (you would actually run into paradoxes if you could it at the same level of hierarchy, I think). A Σ(k+10)-formula would be sufficient I think, though you may not need to go quite that high. Also "it is very difficult to explicitly write down the formula for the case k>100" sounds a little weird. Maybe it would be better to say "it is very difficult to explicitly write down the formula for k that are large by human standards (if k is much larger than 100, for example)". It not like 101 suddenly becomes way harder than 100, for example. k=10^100 or even a billion is obviously out of the question, though (if we require it to be reasonable for a human to write down the formula).