
4.4. VARIATIONS OF PROXIMITY DRAWINGS 135
(a)
(b)
u
q
v
u
q
v
Figure 4.14 Two witnes s Gabriel drawings where q is the witness point: (a) Positive
witness Gabriel drawing. (b) Negative witness Gabriel dr awing.
induced s ub grap h do not have a negative witness Gabriel drawing. It is also pr oved that
all trees are negative witness Gabriel drawable.
Positive witness rectangle of influence drawings are e xp lor ed in [ADH11b]. In this pa-
per, Aronov, Dulieu, and Hurtado show that a tree admits a positive witness rectangle of
influence drawing if and only if it has no three independent edges. The paper also gives
necessary conditions for positive witness re ct ...