Possible typo in Just/Weese's set theory

Question

In Just Weese on page 197 there are the following corollaries:

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Regarding Corollary 24: Is this a typo and should say "$CON(ZF) \not\rightarrow CON(ZF + \exists \text{ "a strongly inaccessible cardinal."})$"?

I can't see anything wrong with the implication "$CON(ZF) \rightarrow CON(ZF + \text{ "there are no strongly inaccessible cardinals."})$".

Many thanks for your help.

Answer 1

The next two paragraph give a proof of Corollary 24. The content of this proof is that if there are no inaccessible cardinals then we are done; otherwise there is a least inaccessible $\lambda$, in which case Lemma 25 proves that $\langle V_\lambda,\overline\in\rangle$ is a model of ZF+"There are no inaccessible cardinals".

In either case we see that the proof actually proves:

$CON(\mathrm{ZF})\nrightarrow CON(\mathrm{ZF}+\exists\text{ a strongly inaccessible cardinal})$

Which also fits the two-liner proof based on Godel's incompleteness theorem which is given right after Corollary 24.