![]() Lehtonen, Erkko ![]() in Proceedings of the Vienna Conference 2005 (AAA70) (2006) For a class C of Boolean functions, a Boolean function f is a C-subfunction of a Boolean function g, if f=g(h1,...,hn), where all the inner functions hi are members of C. Two functions are C-equivalent ... [more ▼] For a class C of Boolean functions, a Boolean function f is a C-subfunction of a Boolean function g, if f=g(h1,...,hn), where all the inner functions hi are members of C. Two functions are C-equivalent, if they are C-subfunctions of each other. The C-subfunction relation is a preorder on the set of all functions if and only if C is a clone. An infinite descending chain of U∞-subfunctions is constructed from certain threshold functions (U∞ denotes the clone of clique functions). [less ▲] Detailed reference viewed: 36 (1 UL)![]() Couceiro, Miguel ![]() ![]() in Discrete Mathematics (2006), 306(24), 3223-3243 The class composition CK of Boolean clones, being the set of composite functions f(g1,...,gn) with f∈C, g1,...,gn∈K, is investigated. This composition CK is either the join C∨K in the Post Lattice or it ... [more ▼] The class composition CK of Boolean clones, being the set of composite functions f(g1,...,gn) with f∈C, g1,...,gn∈K, is investigated. This composition CK is either the join C∨K in the Post Lattice or it is not a clone, and all pairs of clones C,K are classified accordingly. Factorizations of the clone Ω of all Boolean functions as a composition of minimal clones are described and seen to correspond to normal form representations of Boolean functions. The median normal form, arising from the factorization of Ω with the clone SM of self-dual monotone functions as the leftmost composition factor, is compared in terms of complexity with the well-known DNF, CNF, and Zhegalkin (Reed–Muller) polynomial representations, and it is shown to provide a more efficient normal form representation. [less ▲] Detailed reference viewed: 110 (0 UL)![]() Couceiro, Miguel ![]() ![]() in Tsitouras, C.; Simos, T. E.; Psihoyios, G. (Eds.) ICNAAM 2005 (2005) Representations of an arbitrary set of vertices of an n-dimensional cube in terms of convex sets are compared with respect to their complexity. The notion of complexity used in the representations is ... [more ▼] Representations of an arbitrary set of vertices of an n-dimensional cube in terms of convex sets are compared with respect to their complexity. The notion of complexity used in the representations is based on the union, symmetric difference and ternary median operations. Convexity of a set of vertices refers to Hamming distance or, equivalently, to the intersection of cubes with supporting hyperplanes. [less ▲] Detailed reference viewed: 39 (1 UL)![]() Couceiro, Miguel ![]() ![]() in Simos, T.; Maroulis, G. (Eds.) International Conference of Computational Methods in Sciences and Engineering 2004 (ICCMSE 2004) (2004) We present some compositions of clones of Boolean functions that imply factorizations of ?, the clone of all Boolean functions, into minimal clones. These can be interpreted as representation theorems ... [more ▼] We present some compositions of clones of Boolean functions that imply factorizations of ?, the clone of all Boolean functions, into minimal clones. These can be interpreted as representation theorems, providing representations of Boolean functions analogous to the disjunctive normal form, the conjunctive normal form, and the Zhegalkin polynomial representations. [less ▲] Detailed reference viewed: 106 (0 UL) |
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