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isEmpty                                                          (Tag)
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isEmpty : tag -> bool

SYNOPSIS
Tells if a tag is empty.

KEYWORDS
tag.

DESCRIBE
An invocation {isEmpty t} returns {true} just in case {t} is the empty tag.
Only theorems built solely by HOL proof have an empty tag.

FAILURE
Never fails.

EXAMPLE

- Tag.isEmpty (Thm.tag NOT_FORALL_THM);
> val it = true : bool




SEEALSO
Thm.tag, Thm.mk_oracle_thm.

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