不完全三值逻辑在语言表达上的相互比较

深入讨论各种命题联结词含量不完全的三值逻辑的语言表达的能力,完全弄明白了三值系统L3,L3,B3,B3,K3,K3,MP的语言表达能力的等效或不等效关系,特别应当指出的一个结论是：中介命题逻辑MP作为一种命题联结词含量不完全的三值系统而言,它和其他命题联结含量不完全的三值逻辑L3,L3Δ,B3,B3Δ,K3,K3Δ的语言表达能力都不等效,从而也由此体现出MP的一种自身特色。     

The deviation, density, and depth of partially ordered sets

Let P be a poset, and let γ be a linear order type with |γ| ≥ 3. The γ-deviation of P, denoted by γ-dev P, is defined inductively as follows: (1) γ-dev P=0, if P contains no chain of order type γ; (2) γ-dev P = , if γ-dev P and each chain C of type γ in P contains elements a and b such that a<b and [a, b] as an interval of P has γ-deviation <. There may be no ordinal such that γ-dev P = ; i.e., γ-dev P does not exist. A chain is γ-dense if each of its intervals contains a chain of order type γ. If P contains a γ-dense chain, then γ-dev P fails to exist. If either (1) P is linearly ordered or (2) a chain of order type γ does not contain a dense interval, then the converse holds. For an ordinal ξ, a special set S(ξ) is used to study ω_ξ-deviation. The depth of P, denoted by δ(P) is the least ordinal β that does not embed in P^*. Then the following statements are equivalent: (1) ω_ξ-dev P does not exist; (2) S(ξ) embeds in P; and (3) P has a subset Q of cardinality _ξ such that δ(Q^*) = ω_{ξ + 1}. Also ω_ξ-dev P = <ω_{ξ + 1} if and only if |δ(P^*)|_ξ; if these equivalent conditions hold, then ω^β_ξ < δ(P^*) ≤ ω ^{+ 1}_ξ for all β < . Applications are made to the study of chains of submodules of a module over an associative ring.     

Coordinates for the Regular Complex Polygons

Certain projections of the real polytopes {3, 3, 4}, {3, 4,3}, {3, 3, 5} suggest highly symmetric coordinates for the self-reciprocalcomplex polygons 3{3}3, 4{3}4, 3{4}3, 5{3}5 and 3{5}3. Althoughthere are a number of interesting complications, this suggestionis essentially correct and leads to elegant coordinates forall the sporadic complex polygons. Among the by-products ofproducing these coordinates we count most significant our newinsights about 2{6}3 and our simple proof that the 600 verticesof the real polytope {5, 3, 3} are quite unrelated to the 600vertices of either 5{6}2 or 5{4}3.     

The packing of pairs by quadruples

Let X be a finite set of size ν, further let λ be a positive integer and let σ(4,λν) denote the maximum number of quadruples such that each pair of elements of X is contained in at most λ of them. The value of σ(4, 1;ν) has been determined by Brouwer (1979) for all v4. The value of σ(4,λν) has been determined by Billington, Stanton and Stinson (1984) for all ν≡0 (mod 3) and λ>1. In this paper we complete the determination of σ(4,λν) for all ν4 and λ>1.     

邻域并与泛圈图

本文中 ,我们用邻域并对泛圈图进行深入的研究 ,主要取得了“2连通 n( n≥ 3 )阶图 G,满足下列条件之一 ,则 G是泛圈图 : :δ≤ ( n-7) /3 ,N C≥ ( 2 n-3 ) /3 ; :( n-6) /3≤ δ≤ ( n+2 ) /3 ,N C≥ 2 n/3 ; :δ≥ ( n+3 ) /3 ,N C≥ ( 2 n-3 ) /3 .当 3≤ n≤ 14时 ,N C≥ 2 n/3”     

A fixed point theorem and a norm inequality for operator means

There is one to one correspondence between positive operator monotone functions on (0, ∞) and operator connections. For a symmetric connection σ, it is proved that the map X → (AσX)σ(BσX) from positive operators on a Hilbert space to itself, has a unique fixed point. Here σ denotes the dual of σ. It is also proved that |||AσB||| |||A|||σ|||B||| for all unitarily invariant norms ||| · ||| and for all positive operators A,B.     

On cardinal sequences of scattered spaces

It was proved by Dow and Simon that there are 2^ω₁ (as many as possible) pairwise nonhomeomorphic compact, T₂, scattered spaces of height ω₁ and width ω. In this paper, we prove that if is an ordinal withω₁ < ω₂ and θ = κ_ξ: ξ < is a sequence of cardinals such that either κ_ξ = ω or κ_ξ = ω₁ for every ξ < , then there are 2^ω₁ pairwise nonhomeomorphic compact, T₂, scattered spaces whose cardinal sequence is θ.     

A characterization of 3-nets

Laskar introduced 3-nets as a 3 dimensional analogue to Bruck's notion of net. Affine 3-spaces are an example of 3-nets, and cubic lattice graphs provide another example. Freeman introduced and Laskar extended a class of examples of 3-nets, here called Freeman-Laskar 3-nets. We show that every finite 3-net is either a cubic lattice 3-net or a Freeman-Laskar 3-net. We also show that every infinite 3-net either is a cubic lattice 3-net or arises from a vector space over a skew field.     

3-Lie bialgebras and 3-Lie classical Yang–Baxter equations in low dimensions

In this paper, we give low-dimensional examples of local cocycle 3-Lie bialgebras and double construction 3-Lie bialgebras which were introduced in the study of the classical Yang–Baxter equation and Manin triples for 3-Lie algebras. We give an explicit and practical formula to compute the skew-symmetric solutions of the 3-Lie classical Yang–Baxter equation (CYBE). As an illustration, we obtain all skew-symmetric solutions of the 3-Lie CYBE in complex 3-Lie algebras of dimensions 3 and 4 and then the induced local cocycle 3-Lie bialgebras. On the other hand, we classify the double construction 3-Lie bialgebras for complex 3-Lie algebras in dimensions 3 and 4 and then give the corresponding eight-dimensional pseudo-metric 3-Lie algebras.     

Some New Optimal Ternary Linear Codes

Let d₃(n,k) be the maximum possible minimum Hamming distance of a ternary [ n,k,d;3]-code for given values of n and k. It is proved that d₃(44,6)=27, d₃(76,6)=48,d₃(94,6)=60 , d₃(124,6)=81,d₃(130,6)=84 , d₃(134,6)=87,d₃(138,6)=90 , d₃(148,6)=96,d₃(152,6)=99 , d₃(156,6)=102,d₃(164,6)=108 , d₃(170,6)=111,d₃(179,6)=117 , d₃(188,6)=123,d₃(206,6)=135 , d₃(211,6)=138,d₃(224,6)=147 , d₃(228,6)=150,d₃(236,6)=156 , d₃(31,7)=17 and d₃(33,7)=18 . These results are obtained by a descent method for designing good linear codes.     

ContributionsEdge colorings of graphs embeddable in a surface of low genus

In this paper, by using the Discharging Method, we show that any graph with maximum degree Δ 8 that is embeddable in a surface Σ of characteristic χ(Σ) 0 is class one and any graph with maximum degree Δ 9 that is embeddable in a surface Σ of characteristic χ(Σ) = − 1 is class one. For surfaces of characteristic 0 or −1, these results improve earlier results of Mel'nikov.     

On inverse spectrum problems for normal nonnegative matrices

For a set σ with n complex numbers, some sufficient conditions are found for σ to be the spectrum of an n ×n normal (entrywise) nonnegative (positive) matrix. After proving a fundamental theorem and introducing the companion set σ' of σ which consists of real numbers, we prove that if σ' satisfies any known sufficient conditions for a real set to be the spectrum of a nonnegative matrix introduced by Suleimanova, Perfect, Salzmann and Kellogg respectively, then σ is the spectrum of an n×n normal nonnegative matrix.     

On graphs having σ-polynomials of the same degree

Frucht and Giudici classified all graphs having quadratic σ-polynomials. Dhurandhar characterized all graphs having quadratic and cubic σ-polynomials. Here, we give a necessary and sufficient condition for the graphs whose σ-polynomials are of degree k where k is any positive integer. By using this condition, we construct all graphs whose σ-polynomials are of degree 2, 3 and 4. For the quadratic and cubic cases, our results are the same as those of Frucht, Giudici and Dhurandhar's.     

两个互素的立方数之差

令ρ3(n)=∑n=|m|3-|l|3,(m,l)=1 1．本文研究了和式R3(x)=∑n≤xρ3(n)= A3x2／3+B3x1／2+E3(x),并且在黎曼假设下,得到E3(x)=0(x4／15+ε),从而进一步改进了前人的结果．     

Efficient text fingerprinting via Parikh mapping

We consider the problem of fingerprinting text by sets of symbols. Specifically, if S is a string, of length n, over a finite, ordered alphabet Σ, and S′ is a substring of S, then the fingerprint of S′ is the subset φ of Σ of precisely the symbols appearing in S′. In this paper we show efficient methods of answering various queries on fingerprint statistics. Our preprocessing is done in time O(n|Σ|lognlog|Σ|) and enables answering the following queries:

(1)Given an integer k, compute the number of distinct fingerprints of size k in time O(1).

(2)Given a set φΣ, compute the total number of distinct occurrences in S of substrings with fingerprint φ in time O(|Σ|logn).

     

不含三角形的图的λ3-最优性的充分条件

设G=(V,E)是一个连通图,边集S(?)E是一个3-限制性边割,如果G-S是不连通的并且G-S的每个分支至少有三个点.图G的3-限制性边连通度λ_3(G)是G中最小的一个3-限制性边割的基数.图G是λ_3(G)连通的,如果3-限制性边割存在.G是λ_3-最优的,如果λ_3(G)=ξ_3(G),其中ξ_3(G)=min{|[U,(?)]|:U(?)V,|U|=3 and G[U]是连通的).G[U]表示V的子集U的导出子图,(?)=V\U表示U的补.[U,(?)]是一条边的一个端点在U中另一个端点在(?)中的边的集合.本文给出了不含三角形的图是λ_3-最优的一些充分条件.     

Impulsive effects on global existence of solutions for degenerate semilinear parabolic equations

Let q be a nonnegative real number, and λ and σ be positive constants. This article studies the following impulsive problem: for n = 1, 2, 3,…,

. The number λ^* is called the critical value if the problem has a unique global solution u for λ < λ^*, and the solution blows up in a finite time for λ > λ^*. For σ < 1, existence of a unique λ^* is established, and a criterion for the solution to decay to zero is studied. For σ > 1, existence of a unique λ^* and three criteria for the blow-up of the solution in a finite time are given respectively. It is also shown that there exists a unique T^* such that u exists globally for T> T^*, and u blows up in a finite time for T < T^*.     

An improved upper bound for Ramsey number N (3, 3, 3, 3; 2)

The Ramsey number N(3,3,3,3; 2) is the smallest integer n such that each 4-coloring by edges of the complete graph on n vertices contains monochromatic triangles. It is well known that 51 ≤ N(3, 3, 3, 3; 2) ≤ 65. Here we prove that N(3, 3, 3, 3; 2) ≤ 64.     

Existence results for doubly near resolvable (υ, 3, 2)-BIBDs

Let V be a set of υ elements. A (1, 2; 3, υ, 1)-frame F is a square array of side v which satisfies the following properties. We index the rows and columns of F with the elements of V, V={x₁,x₂,…,x_υ}. (1) Each cell is either empty or contains a 3-subset of V. (2) Cell (x_i, x_i) is empty for i=1, 2,…, υ. (3) Row x_i of F contains each element of V−{x_i} once and column x_i of F contains each element of V−{x_i} once. (4) The collection of blocks obtained from the nonempty cells of F is a (υ, 3, 2)-BIBD. A (1, 2; 3, υ, 1)-frame is a doubly near resolvable (υ, 3, 2)-BIBD. In this paper, we first present a survey of existence results on doubly near resolvable (υ, 3, 2)-BIBDs and (1, 2; 3, υ, 1)-frames. We then use frame constructions to provide a new infinite class of doubly near resolvable (υ, 3, 2)-BIBDs by constructing (1, 2; 3, υ, 1)-frames.     

Changing cofinalities and collapsing cardinals in models of set theory

If a˜cardinal κ₁, regular in the ground model M, is collapsed in the extension N to a˜cardinal κ₀ and its new cofinality, ρ, is less than κ₀, then, under some additional assumptions, each cardinal λ>κ₁ less than cc(P(κ₁)/[κ₁]^<κ₁) is collapsed to κ₀ as well. If in addition N=M[f], where f : ρ→κ₁ is an unbounded mapping, then N is a˜|λ|=κ₀-minimal extension. This and similar results are applied to generalized forcing notions of Bukovský and Namba.