  The goal of this note is to explore the relationship between the Folland-Kohn
basic estimate and the $Z(q)$-condition. In particular, on unbounded
pseudoconvex (resp., pseudoconcave) domains, we prove that the Folland-Kohn
basic estimate is equivalent to uniform strict pseudoconvexity (resp.,
pseudoconcavity). As a corollary, we observe that despite the Siegel upper half
space being strictly pseudoconvex and biholomorphic to a the unit ball, it
fails to satisfy uniform strict pseudoconvexity and hence the Folland-Kohn
basic estimate fails.
  On unbounded non-pseudoconvex domains, we show that the Folland-Kohn basic
estimate on $(0,q)$-forms implies a uniform $Z(q)$ condition, and conversely,
that a uniform $Z(q)$ condition with some additional hypotheses implies the
Folland-Kohn basic estimate for $(0,q)$-forms.
