Recreational Book Research Articles

Splitting a Polygon into Two Congruent Pieces

It is quite easy to find the solution to this particular splitting problem (as shown in Fig. l(b)), but there are certainly cases where the solution is far from obvious; at a graduation party in Stockholm 1994 (with a lot of mathematicians among the guests), nobody was able to solve all the problems in the column mentioned above. On such occasions an effective algorithm that solves the problem would come in handy. It is the aim of this paper to provide such an algorithm. At the end of the paper I show that a theorem on splitting convex shapes follows from the algorithm. I also give a few nice problems for the reader to practise on. According to my friend Doron Zeilberger, this kind of problem goes back to the great puzzle inventor Henry Dudeney who wrote several books with mathematical amusement problems in the first decades of this century, e.g. [1]. In a recreational math book by Fred Schuh [3], I found a puzzle of this kind, and also one variant where the polygon should be split in four congruent quarters. I do not claim to have an algorithm for variants with more than two parts, but I would love to see one! After writing the first version of this paper, I obseIved an instance of the splitting problem on one of a series of mathematical posters on the wall by the MIT math department staircase. This poster referred to an eighteen year old

大学図書館蔵書論

Since the end of the war, librariarship in Japan have tended to put more emphasis on services rather than library materials. But no library service can be rendered without a good collection. To build a good collection, a well organized acquisition policy is indispensable.Any acquisition policy statement should make clear at least the following five factors: 1. objectives of the university; 2. objectives of the library; 3. the location of responsibility for selection; 4. the location of responsibility for the book funds; 5. those who participate in selection.The university library collection can be considered from the standpoint of the types of material in it; reference books, periodicals, books which reveal history and contemporary thought in all the subject fields that are studied in the curriculum, government documents, and recreational books. From the standpoint of the quality of the material, the library collection consists of classics, standard works, and special material for highly specialized research. From still other point of view, university library material can be divided into two great groups; those which extend the frontiers of knowledge and secondary or teaching materials such as texts, syntheses, introductory works, etc. More difficulties exist in selection of the first group of material.In the process of building a library collection, planning, putting the plan into practice, examination and evaluation of the results are a series of essential activities. Evaluation is a final stage and at the same a starting point. There is no single standard measuring device for evaluation, and several procedures should be used to obtain a more or less accurate picture of the status of the collection. The chief methods commonly used are: 1. a subjective or impressionistic method, asking opinions of persons who undertake evaluation, 2. check list method, i.e. check of holdings against standard lists and bibliogarphies, 3. identification of levels of collections, 4. check of current circulation records, 5. check of the records of materials requested and not in the holdings, and 6. check of the expenditures for libray materials.Nowadays many universities, especially private ones, are in extreme financial difficulty, and, since the library is expensive, it is often regarded as a burden to the university. But the same university thinks little of paying much money for the rental fee of a large computer or buying expensive laboratory equipment which will become obsolete very soon. The research library never becomes obsolete and is a permanent investment of the university. Bearing this in mind, the librarians should take courage in building a good library collection for both present and future needs.