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。     

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 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.     

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”     

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.     

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.     

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.     

Borel ideals vs. Borel sets of countable relations and trees

For every μ < ω₁, let I_μ be the ideal of all sets S ω^μ whose order type is <ω^μ. If μ = 1, then I₁ is simply the ideal of all finite subsets of ω, which is known to be Σ⁰₂-complete. We show that for every μ < ω₁, I_μ is Σ⁰_2μ-complete. As corollaries to this theorem, we prove that the set WO_ωμ of well orderings Rω × ω of order type <ω^μ is Σ⁰_2μ-complete, the set LP_μ of linear orderings R ω × ω that have a μ-limit point is Σ⁰_2μ+1-complete. Similarly, we determine the exact complexity of the set LT_μ of trees T ^<ωω of Luzin height <μ, the set WR_μ of well-founded partial orderings of height <μ, the set LR_μ of partial orderings of Luzin height <μ, the set WF_μ of well-founded trees T ^<ωω of height <μ(the latter is an old theorem of Luzin). The proofs use the notions of Wadge reducibility and Wadge games. We also present a short proof to a theorem of Luzin and Garland about the relation between the height of ‘the shortest tree’ representing a Borel set and the complexity of the set.     

3-LIE BIALGEBRAS

3-Lie algebras have close relationships with many important fields in mathemat- ics and mathematical physics. This article concerns 3-Lie algebras. The concepts of 3-Lie coalgebras and 3-Lie bialgebras are given. The structures of such categories of algebras and the relationships with 3-Lie algebras are studied. And the classification of 4-dimensional 3-Lie coalgebras and 3-dimensional 3-Lie bialgebras over an algebraically closed field of char- acteristic zero are provided.     

The reflection length of a transformation in the unitary group over a finite field

Let U be the unitary group over a finite field K where [K]≠3 and char K≠2. Every transformation π in U with detπ = ±1 is a product of reflections. We determine the length t of every such transformation π i.e. for each π we find reflections σ_i in U such that π=σ₁ σ_t and so that no factorization of π into fewer than t reflections exists.     

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．     

点可迁图的限制边连通性

3限制边割是连通图的一个边割, 它将此图分离成阶不小于3的连通分支. 图G的最小3限制边割所含的边数称为此图的3限制边连通度, 记作λ\-3(G). 它以图G的3阶连通点导出 子图的余边界的最小基数ξ_3(G)为上界. 如果λ_3(G)=ξ_3(G), 则称图G是极大3限制边连通的 . 已知在某种程度上,3限制边连通度较大的网络有较好的可靠性. 作者在文中证明: 如果k正则连通点可迁图的 围长至少是5, 那么它是是极大3限制边连通的.     

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 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.     

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).

     

On the on-line chromatic number of the family of on-line 3-chromatic graphs

Let the family OL(3) contain all graphs which can be colored on-line with 3 colors. Gyárfás and Lehel suggested the problem of determining the on-line chromatic number χ^*(OL(3)) of OL(3). They showed that 4 χ^*(OL(3)) 16. We present an algorithm that colors every on-line-3-chromatic graph with 4 colors. Thus χ^*(OL(3)) = 4.     

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 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.     

(1/α)-Self similar α-stable processes with stationary increments

In this note we settle a question posed by Kasahara, Maejima, and Vervaat. We show that the α-stable Lévy motion is the only (1/α)-self-similar α-stable process with stationary increments if 0 < α < 1. We also introduce new classes of (1/α)-self-similar α-stable processes with stationary increments for 1 < α < 2.     

3-Lie bialgebras

3-Lie algebras have close relationships with many important fields in mathematics and mathematical physics. This article concerns 3-Lie algebras. The concepts of 3-Lie coalgebras and 3-Lie bialgebras are given. The structures of such categories of algebras and the relationships with 3-Lie algebras are studied. And the classification of 4-dimensional 3-Lie coalgebras and 3-dimensional 3-Lie bialgebras over an algebraically closed field of characteristic zero are provided.