88,599 research outputs found

    On Vanishing of {K}ronecker Coefficients

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    It is shown that: (1) The problem of deciding positivity of Kronecker coefficients is NP-hard. (2) There exists a positive (#P\# P)-formula for a subclass of Kronecker coefficients whose positivity is NP-hard to decide. (3) For any 0<ϔ≀10 < \epsilon \le 1, there exists 0<a<10<a<1 such that, for all mm, there exist Ω(2ma)\Omega(2^{m^a}) partition triples (λ,ÎŒ,ÎŒ)(\lambda,\mu,\mu) in the Kronecker cone such that: (a) the Kronecker coefficient kÎŒ,Όλk^\lambda_{\mu,\mu} is zero, (b) the height of ÎŒ\mu is mm, (c) the height of λ\lambda is ≀mÏ”\le m^\epsilon, and (d) ∣λ∣=âˆŁÎŒâˆŁâ‰€m3|\lambda|= |\mu| \le m^3. The last result takes a step towards proving the existence of occurrence-based representation-theoretic obstructions in the context of the GCT approach to the permanent vs. determinant problem. Its proof also illustrates the effectiveness of the explicit proof strategy of GCT

    P vs NP: P is Equal to NP: Desired Proof

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    Computations and computational complexity are fundamental for mathematics and all computer science, including web load time, cryptography (cryptocurrency mining), cybersecurity, artificial intelligence, game theory, multimedia processing, computational physics, biology (for instance, in protein structure prediction), chemistry, and the P vs. NP problem that has been singled out as one of the most challenging open problems in computer science and has great importance as this would essentially solve all the algorithmic problems that we have today if the problem is solved, but the existing complexity is deprecated and does not solve complex computations of tasks that appear in the new digital age as efficiently as it needs. Therefore, we need to realize a new complexity to solve these tasks more rapidly and easily. This paper presents proof of the equality of P and NP complexity classes when the NP problem is not harder to compute than to verify in polynomial time if we forget recursion that takes exponential running time and goes to regress only (every problem in NP can be solved in exponential time, and so it is recursive, this is a key concept that exists, but recursion does not solve the NP problems efficiently). The paper’s goal is to prove the existence of an algorithm solving the NP task in polynomial running time. We get the desired reduction of the exponential problem to the polynomial problem that takes O(log n) complexity

    Uniformly generated submodules of permutation modules Over fields of characteristic 0

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    AbstractThis paper is motivated by a link between algebraic proof complexity and the representation theory of the finite symmetric groups. Our perspective leads to a new avenue of investigation in the representation theory of Sn. Most of our technical results concern the structure of “uniformly” generated submodules of permutation modules. For example, we consider sequences {Wn}n∈N of submodules of the permutation modules M(n−k,1k) and prove that if the sequence Wn is given in a uniform (in n) way – which we make precise – the dimension p(n) of Wn (as a vector space) is a single polynomial with rational coefficients, for all but finitely many “singular” values of n. Furthermore, we show that dim(Wn)<p(n) for each singular value of n≄4k. The results have a non-traditional flavor arising from the study of the irreducible structure of the submodules Wn beyond isomorphism types. We sketch the link between our structure theorems and proof complexity questions, which are motivated by the famous NP vs. co-NP problem in complexity theory. In particular, we focus on the complexity of showing membership in polynomial ideals, in various proof systems, for example, based on Hilbert's Nullstellensatz

    Algorithmic aspects of disjunctive domination in graphs

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    For a graph G=(V,E)G=(V,E), a set D⊆VD\subseteq V is called a \emph{disjunctive dominating set} of GG if for every vertex v∈V∖Dv\in V\setminus D, vv is either adjacent to a vertex of DD or has at least two vertices in DD at distance 22 from it. The cardinality of a minimum disjunctive dominating set of GG is called the \emph{disjunctive domination number} of graph GG, and is denoted by Îł2d(G)\gamma_{2}^{d}(G). The \textsc{Minimum Disjunctive Domination Problem} (MDDP) is to find a disjunctive dominating set of cardinality Îł2d(G)\gamma_{2}^{d}(G). Given a positive integer kk and a graph GG, the \textsc{Disjunctive Domination Decision Problem} (DDDP) is to decide whether GG has a disjunctive dominating set of cardinality at most kk. In this article, we first propose a linear time algorithm for MDDP in proper interval graphs. Next we tighten the NP-completeness of DDDP by showing that it remains NP-complete even in chordal graphs. We also propose a (ln⁥(Δ2+Δ+2)+1)(\ln(\Delta^{2}+\Delta+2)+1)-approximation algorithm for MDDP in general graphs and prove that MDDP can not be approximated within (1−ϔ)ln⁥(∣V∣)(1-\epsilon) \ln(|V|) for any Ï”>0\epsilon>0 unless NP ⊆\subseteq DTIME(∣V∣O(log⁥log⁥∣V∣))(|V|^{O(\log \log |V|)}). Finally, we show that MDDP is APX-complete for bipartite graphs with maximum degree 33

    On the Complexity of Spill Everywhere under SSA Form

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    Compilation for embedded processors can be either aggressive (time consuming cross-compilation) or just in time (embedded and usually dynamic). The heuristics used in dynamic compilation are highly constrained by limited resources, time and memory in particular. Recent results on the SSA form open promising directions for the design of new register allocation heuristics for embedded systems and especially for embedded compilation. In particular, heuristics based on tree scan with two separated phases -- one for spilling, then one for coloring/coalescing -- seem good candidates for designing memory-friendly, fast, and competitive register allocators. Still, also because of the side effect on power consumption, the minimization of loads and stores overhead (spilling problem) is an important issue. This paper provides an exhaustive study of the complexity of the ``spill everywhere'' problem in the context of the SSA form. Unfortunately, conversely to our initial hopes, many of the questions we raised lead to NP-completeness results. We identify some polynomial cases but that are impractical in JIT context. Nevertheless, they can give hints to simplify formulations for the design of aggressive allocators.Comment: 10 page
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