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1.
A generalization is a statement that is true about many instances.The following story is aboutmaking a generalization.Francie lives in Phoenix.She has a telephone in her room.She pays for all long-distance callsshe makes.One Sunday she called her cousin Meg in San Diego.As they talked,Francie forgot  相似文献   

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Wangqiangthoughthekneweverythingaboutdiagonalsandpolygons.Butthisquestionhadhimstumped :Howmanydiagonalsdoesa 13 gonhave ?Hereadthequestioncarefully .Itwaseasytounderstand .Hedrewapictureofa 13 gin .Hestarteddrawingdiagonalsandquicklygaveupthisapproach .Hetho…  相似文献   

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In this note, a method of converting a rhotrix to a special form of matrix termed a ‘coupled matrix’ is proposed. The special matrix can be used to solve various problems involving n?×?n and (n?–?1)?×?(n?–?1) matrices simultaneously.  相似文献   

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In[1], C.Berge has modified Theorem 1 of [2]to a theorem which is a charac-terization of maximum c-Matchings in a hypergraph (see[1], P.416, Theorem 2),and at the same time can be considered as a generalization of Berge's theorem on  相似文献   

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Bar graphs are convenient for showing comparisons among items.The bars may be either horizontal or vertical,and they are used to show the amounts of different items.Figure 1 is an example of a typical bar graph.The graph shows the average sales price of existing homes in the Northeast United States for three years——1970,1980,and 1997.  相似文献   

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Magazines and newspapers often display information using circle,bar,and line graphs.The following examples illustrate how estimation techniques can be applied to each of these graphs. Circle graphs,also called pie charts,show how a whole quantity is divided into parts.Circle  相似文献   

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FactorizationsOrthogonaltoaSubgraphinGraphsLiGuojun(李国君)LiuGuizhen(刘桂真)(Dept.,ofMath.andSystemsScience,ShandongUniversity,Jin...  相似文献   

10.
Let M be a matroid with rank function r, and let eE(M). The deletion–contraction polymatroid with rank function f=rM?e+rM/e will be denoted Pe(M). Notice that Pe(M) is uniquely determined by M and e. Similarly, a deletion–contraction polymatroid determines M, unless e is a loop or co-loop. This paper will characterize all polymatroids of this deletion–contraction form by giving the set of excluded minors. Vertigan conjectured that the class of GF(q)-representable deletion–contraction polymatroids is well-quasi-ordered. From this attractive conjecture, both Rota’s Conjecture and the WQO Conjecture for GF(q)-representable matroids would follow.  相似文献   

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Necessary conditions are found for a centralizer near-ring MA(G) to be isomorphic to a matrix near-ring, where G is a finite group which is cyclic as an MA(G)-module There are centralizer near-rings which are matrix near-rings. A class of such near-rings is exhibited. Examples of centralizer near-rings which are not matrix near-rings are given.  相似文献   

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It is shown that there is no good answer to the question of the title, even if we restrict our attention to S et-based topological categories. Although very closely related, neither the natural notion of c-finality (designed in total analogy to c-initiality) nor the notion of c-quotient (modelled after the behaviour of topological quotient maps) provide universally satisfactory concepts. More dramatically, in the category T op with its natural Kuratowski closure operator k, the class of k-final maps cannot be described as the class of c-quotient maps for any closure operator c, and the class of k-quotients cannot be described as the class of c-final maps for any c. We also discuss the behaviour of c-final maps under crossing with an identity map, as in Whitehead's Theorem. In T op, this gives a new stability theorem for hereditary quotient maps.  相似文献   

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Let Ω be a bounded smooth domain in RN(N≥3).Assuming that 0 0 are constants,we consider the existence results for positive solutions of a class of fractional elliptic system below,■Under some assumptions of hi(x,u,v,▽u,▽v)(i=1,2),we get a priori bounds of the positive solutions to the problem(1.1) by the blow-up methods and rescaling argument.Based on these estimates and degree theory,we establis...  相似文献   

17.
赵培标 《数学季刊》1996,11(2):56-59
TheIsometryofRiemannianManifoldtoaSphereZhaoPeibiao(赵培标)(Dept.ofMath.,AnhuiInstituteofFinance&Trade,233041)Abstract:Inthispap...  相似文献   

18.
In this paper, we prove several results concerning meromorphic functions f and g of hyperorder less than one such that f^(j) and g^(j) have the same zeros and poles for j=0, 1, 2. We provide some examples to show that our results are sharp.  相似文献   

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In this paper, the author provides an efficient linear recurrence relation for the number of partitions of n into parts not congruent to 0, \(\pm 1\), \(\pm 8\), \(\pm 9\) and \(10 \pmod {20}\). A simple criterion for deciding whether this number is odd or even is given as a corollary of this result. Some results involving overpartitions and partitions into distinct parts have been derived in this context.  相似文献   

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