We study properties of the functional \begin{eqnarray} \mathscr{F}_{{\rm loc}}(u,\Omega):=
\inf_{(u_{j})}\bigg\{ \liminf_{j\rightarrow\infty}\int_{\Omega}f(\nabla u_{j})\ud
x\, \left| \!\!\begin{array}{rl} & (u_{j})\subset W_{{\rm
loc}}^{1,r}\left(\Omega, \RN\right) \\ & u_{j}\tostar u\,\,\textrm{in
}\BV\left(\Omega, \RN\right) \end{array} \right. \bigg\}, \end{eqnarray}
where u ∈
BV(Ω;RN), and
f:RN ×
n → R is continuous and satisfies
0 ≤ f(ξ) ≤
L(1 + | ξ |
r). For r ∈ [1,2),
assuming f
has linear growth in certain rank-one directions, we combine a result of [A. Braides and
A. Coscia, Proc. Roy. Soc. Edinburgh Sect. A 124 (1994)
737–756] with a new technique involving mollification to prove an upper bound for
Floc. Then, for
\hbox{$r\in[1,\frac{n}{n-1})$}
, we prove that
Floc satisfies
the lower bound \begin{equation*} \scF_{{\rm loc}}(u,\Omega) \geq \int_{\Omega}
f(\nabla u (x))\ud x + \int_{\Omega}\finf
\bigg(\frac{D^{s}u}{|D^{s}u|}\bigg)\,|D^{s}u|, \end{equation*}
provided f is quasiconvex, and the recession function
f∞ (defined as
\hbox{$ f^{\infty}(\xi):= \overline{\lim}_{t\rightarrow\infty}f(t\xi )/t$}
) is assumed to be finite in
certain rank-one directions. The proof of this result involves adapting work by
[Kristensen, Calc. Var. Partial Differ. Eqs. 7 (1998)
249–261], and [Ambrosio and Dal Maso, J. Funct. Anal. 109
(1992) 76–97], and applying a non-standard blow-up technique that exploits fine
properties of BV maps. It also makes use of the fact that Floc has a measure
representation, which is proved in the appendix using a method of [Fonseca and Malý,
Annal. Inst. Henri Poincaré Anal. Non Linéaire 14 (1997)
309–338].