“…they are "external" to the logic program, whereas dynamic preferences appear within the logic program and are determined "on the fly". The most common form of preference consists in specifying preference conditions among rules (Brewka, 1996;Brewka & Eiter, 1999Delgrande, Schaub, & Tompits, 2000a, 2000bGelfond & Son, 1997;Schauba & Wang, 2001;, 2004Wang, Zhou, & Lin, 2000;Zhang & Foo, 1997), whereas, some recent proposals admit the expression of preference relations among atoms (Brewka, Niemela, & Truszczynski, 2003;Brewka, 2004;Sakama & Inoue, 2000;Wakaki et al, 2003). More sophisticated forms of preferences also allow the specification of priorities between conjunctions (disjunctions) of literals (Brewka et al, 2003;Delgrande et al, 2000a;Sakama & Inoue, 2000) and numerical penalties for suboptimal options (Brewka, 2004).…”