Abstract
Let X
m,n
be the Segre–Veronese variety ℙ
m
× ℙ
n
embedded by
the morphism given by O(1, 2). In this paper, we provide two
functions such that the sth secant variety of
X
m,n
has the expected dimension if
or
.
We also present a conjecturally complete list of defective
secant varieties of such Segre–Veronese varieties.