停車就是彈硬幣
在這個科展中我們要研究兩個非常有趣的問題:\r 停車場問題 與 彈硬幣遊戲.\r 停車場問題是這樣的:在一條單行道上有n個車位,編號從1到n。現在有n個司機排成一排要進入停車。但是每個司機都有怪癖,各自有最想要停的位子。他們依序將車子開進單行道,如果想要停的位子是空的,當然停在這個位子。但是如果不巧那個位子已經被停了,不得已只好找下一個空位,姑且停之。但是如果往下找都沒有空位,由於是單行道,司機就只好開走不停了。\r 比如說,如果現在有五輛車,司機的喜好分別是(3,1,2,5,2)。則五輛車都可以順利停車。但是司機的喜好如果是(3,1,4,5,4),有些車就無法停車了。\r 彈硬幣遊戲是這樣的:考慮圓內接正n+1邊形,任意兩點都連線。這正n+1邊形中有一個頂點P是特殊的,每個頂點上一開始都放有一些硬幣(各點硬幣數可以不同)。如果P以外的某個頂點上的硬幣數n個,我們可以對這個頂點進行操作:一次操作是指將這個頂點上的硬幣各分一個給每個其他頂點。點P只在其他點都無法操作時操作。我們不理會頂點P上的錢數,因此這個遊戲可以無限地玩下去。
共點圓、共圓點
我的研究是利用一些特殊的手法來探討所有情況皆會產生共點圓或共圓點。在一個由四條直線(無平行線組、無共點)所構成的圖形中,可以找到四個三角形及它們的外接圓。我知道它會共點,在此稱其為限制點。且若再添加一條直線,則可以任意的取出四條直線,分別找出它的限制點,而這些限制點又會共圓,吾稱其為限制圓。我欲證明此種情況會不斷延續下去。即是六條線時又會有限制點,七條線時又會有限制圓…。在本研究中,我利用了數學歸納法、特殊的編號方法以及「方向角」來做出此證明。由於固定的線組對應至固定的限制點或限制圓,希望能向找出其性質的方向發展。In my study, I use some skills to discuss all the situations which satisfy following conditions. The result is that concurrent circles or concyclic points will be found in every situation. In a graph consisting of four lines, conforming to conditions that any three lines won’t be parallel or intersect at one point, I can find out four triangles and their circumscribed circles. I know these circumscribed circles will be concurrent and I call the point at which all the circles meet “restricted point”. If another line is additionally added in the graph, I can discover that restricted points determined by any four lines in the graph will be concyclic. I call the circle “restricted circle”. What I want to prove is that the above situation will go on. In other words, restricted points will exist when I have six lines, and restricted circles will exist when I have seven lines and so on. In my study, I used Principal of Mathematical Induction, special ways of numbering points and circles, and “orientated angle” to prove my hypothesis. Because of particular line groups corresponding with particular restricted points or restricted circles, the further work I want to attain is to find the relation of them.
費瑪也瘋狂-平面上存在障礙時連接三定點的最佳網絡問題
在一個有障礙的平面上,給三個定點,我們探討連接此三點的最佳網絡。我們討論了諸如直線、射線、線段、圓、網格狀、三角形……等類的障礙,當網絡每穿越障礙一次,就必須付出代價,例如「拖延5 分鐘」。所以,設網絡穿越障礙的次數為y ,則網絡除了原本的總長度之外,還額外加入y 倍某固定數值的損耗。我們以費瑪點的各種性質及三角形不等式等方法為工具,就不同的穿越障礙次數綜合比較,而找出最佳網絡。在某些情況下,最佳網絡不是以費瑪點來連接三點,而是在障礙(如:直線)上找出符合某種與餘弦值相關特殊性質的點,以該點來連接三點,而此網絡可用GSP 軟體相當精確地作出。另外,我們也探討在考慮障礙造成損耗的情況下,兩點間的「實際距離」為何。 最後,我們考慮「混合障礙」問題。在此類問題中,除了前面所討論的障礙,還另加了如同「河流」的兩平行直線間區域之障礙,在這種障礙區域中,網絡的長度要乘以數倍來計算。我們發現,此類問題的最佳網絡也可用特定的正弦條件配合GSP 而相當精確地作出來。;Considering various kinds of obstacles in a plane, such as a line, a segment, a ray, a circle, a triangle or chessboard grids, which function like a red light, we research into the problem of finding the optimal network connecting three given points A, B, C in the plane amidst obstacles described above. Each time when the network crosses an obstacle, it will cause losses, such as five minute’s delay or a loss of one hundred dollars. Taking advantage of Fermat points, some basic inequalities concerning triangles and some special qualities about sine or cosine functions, we obtain the optimal networks in different situations. Besides, we consider what the “real distance” between two points is when there are obstacles in a plane. We also put another obstacle, including a line and a weighted region between two parallel lines, into consideration. In the region, like a river or a muddy ground in real life, the length of the network should be multiplied by a fixed time. Furthermore, we can use GSP to make the networks very accurately.
在generalized Petersen graph P(n,5)中的hyper Hamiltonian
Generalized Petersen graph P(n,k),定義為n 為不小於2 的整數以及1≤ k ≤ n−1,有頂點{ u0, u1, . . . , un−1, v0 , v1 , . . . , vn−1 },及路徑{ uiui+1 , uivi , vivi+k:1≤ i ≤ n−1 }。在 [2] 中,我們可以知道P(n,5) 是Hamiltonian 等價於當n≠11。
在這一篇報告中,我們證明當generalized Petersen graph P(n,5) 是hyper Hamiltonian(一種Hamiltonian graph 再去掉任何一點後,仍然是Hamiltonian graph)的充要條件是n 為不等於11 的奇數且n ≥ 7。
The generalized Petersen graph P(n,k), n ≥ 2 and 1≤ k ≤ n−1, has vertex-set { u0, u1, . . . , un−1, v0 , v1 , . . . , vn−1 } and edge-set { uiui+1 , uivi , vivi+k:1≤ i ≤ n−1 with subscripts reduced modulo n}. And we can know that P(n,5) is Hamiltonian if and only if n≠11 from [2].In this paper it is proved that generalized Petersen graph P(n,5) is Hyper Hamiltonian (A Hamiltonian graph can still be a Hamiltonian graph when any one of the nodes fault) if and only if n is odd and n≠11.