大般涅槃經義記 3.6

3.6

下即如來「名不空空」是第九十明異外道所得解脫。先列其名，外道解脫虛誑無實名為「空空」，真不同彼名「不空空」。次釋其相，先解空空，言「空空者無所有」釋其空義，「即是外道尼乾解脫」就人指斥，「而是尼乾實無解脫」就人解空，「真不如是」明有異空。結即可知。

Below, "is none other than the Tathāgata, called not empty-empty" is the ninetieth, clarifying that it is distinct from the liberation attained by non-Buddhists. It first lists its name: the liberation of non-Buddhists is illusory and without reality, named "empty-empty"; the true is not like that, named "not empty-empty". Next it explains its characteristics: first explaining empty-empty: saying "empty-empty means having nothing at all" explains its meaning of emptiness; "it is none other than the liberation of the non-Buddhist Nirgrantha" criticizes in terms of the person; "yet this Nirgrantha in reality has no liberation" explains emptiness in terms of the person; "the true is not like this" clarifies that it has a distinct emptiness. The conclusion can be known.