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Published online by Cambridge University Press: 20 July 2022
In [17], we introduced an extensional variant of generic realizability [22], where realizers act extensionally on realizers, and showed that this form of realizability provides inner models of $\mathsf {CZF}$ (constructive Zermelo–Fraenkel set theory) and
$\mathsf {IZF}$ (intuitionistic Zermelo–Fraenkel set theory), that further validate
$\mathsf {AC}_{\mathsf {FT}}$ (the axiom of choice in all finite types). In this paper, we show that extensional generic realizability validates several choice principles for dependent types, all exceeding
$\mathsf {AC}_{\mathsf {FT}}$. We then show that adding such choice principles does not change the arithmetic part of either
$\mathsf {CZF}$ or
$\mathsf {IZF}$.