100 research outputs found
Width Hierarchy for k-OBDD of Small Width
In this paper was explored well known model k-OBDD. There are proven width
based hierarchy of classes of boolean functions which computed by k-OBDD. The
proof of hierarchy is based on sufficient condition of Boolean function's non
representation as k-OBDD and complexity properties of Boolean function SAF.
This function is modification of known Pointer Jumping (PJ) and Indirect
Storage Access (ISA) functions.Comment: 8 page
On oblivious branching programs with bounded repetition that cannot efficiently compute CNFs of bounded treewidth
In this paper we study complexity of an extension of ordered binary decision diagrams (OBDDs) called c-OBDDs on CNFs of bounded (primal graph) treewidth. In particular, we show that for each k ≥ 3 there is a class of CNFs of treewidth k for which the equivalent c-OBDDs are of size Ω(nk/(8c−4)). Moreover, this lower bound holds if c-OBDDs are non-deterministic and semantic. Our second result uses the above lower bound to separate the above model from sentential decision diagrams (SDDs). In order to obtain the lower bound, we use a structural graph parameter called matching width. Our third result shows that matching width and pathwidth are linearly related
The satisfiability problem for probabilistic ordered branching programs
We show that the satisfiability problem for bounded-error probabilistic ordered branching programs is \NP -complete. If the error is very small, however (more precisely, if the error is bounded by the reciprocal of the width of the branching program), then we have a polynomial-time algorithm for the satisfiability problem
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