朱偉麗 魏祥林
摘 要:為了研究?jī)?nèi)含k個(gè)H-點(diǎn)的H-多邊形的邊界特性和幾何結(jié)構(gòu),針對(duì)正六邊形阿基米德鋪砌,研究鋪砌上的H-三角形內(nèi)部H-點(diǎn)和邊界H-點(diǎn)的關(guān)系。首先,通過(guò)分析H-三角形的三元組(α,β,γ),確定所有可能滿足要求的三元組;其次,利用位級(jí)線理論和鋪砌點(diǎn)分布特性,排除不能實(shí)現(xiàn)的三元組;最后,證明內(nèi)含k個(gè)H-點(diǎn)且邊界H-點(diǎn)數(shù)為3k+5的H-三角形存在,且只有2種構(gòu)圖,并給出這2種構(gòu)圖的具體構(gòu)造。結(jié)果表明,在能夠確定三角形所有可能的三元組條件下,H-三角形滿足給定邊界點(diǎn)數(shù)的圖形結(jié)構(gòu)是確定的。研究結(jié)果豐富了阿基米德鋪砌的相關(guān)理論,也為阿基米德鋪砌相關(guān)問(wèn)題的研究提供了重要的理論依據(jù)。
關(guān)鍵詞:離散數(shù)學(xué);離散幾何;阿基米德鋪砌;正六邊形鋪砌;H-三角形;H-點(diǎn)
H-triangle with k interior H-points and 3k+5 boundary H-points
ZHU Weili,WEI Xianglin
(School of Sciences, Hebei University of Science and Technology, Shijiazhuang, Hebei 050018, China)
Abstract:In order to study the boundary characteristics and geometric structure of an H-polygon with k interior? H-points,the relationship between the interior H-points and boundary H-points of the H-triangle in a regular hexagonal Archimedean tiling was studied. Firstly, by analyzing the triple (α,β,γ)? of H-triangle, the triples that may meet the requirements were determined. Then, the impossible triples were excluded by using the theory of level and the distribution characteristics of tiling points. Finally, H-triangle with k interior H-points and 3k+5 boundary H-points was obtained. Considering there were only two types of configurations, the specific constructions of these two configurations were given. The results show that the configurations of the H-triangle which satisfies the given number of boundary H-points are certain under the condition that all possible triples of triangle can be determined. The research results enrich the related theories of Archimedean tiling, and provide an important theoretical basis for the research of related problems of Archimedean tiling.
Keywords:discrete mathematics;discrete geometry;Archimedean tiling; regular hexagonal tiling; H-triangle; H-point
離散與組合幾何[1-2]中的一個(gè)重要研究問(wèn)題是阿基米德鋪砌[3]問(wèn)題,阿基米德鋪砌是指用一種或多種正多邊形鋪砌全平面,且要求鋪砌的每個(gè)頂點(diǎn)的特征相同。如果阿基米德鋪砌中圍繞一頂點(diǎn)的鋪砌元按環(huán)形循序是n1-邊形、n2-邊形等,則稱該鋪砌屬[n1,n2,…]型,阿基米德鋪砌共有11種[4-8]。正六邊形阿基米德鋪砌,即[6.6.6]鋪砌,是由邊長(zhǎng)為單位長(zhǎng)度的正六邊形構(gòu)成的平面鋪砌。設(shè)H是[6.6.6]鋪砌上正六邊形的頂點(diǎn)集,H中的點(diǎn)稱做H-點(diǎn),頂點(diǎn)落在H上的多邊形稱為H-多邊形。1988年,DING等[9]針對(duì)[6.6.6]鋪砌給出了新的PICK型定理,為研究[6.6.6]鋪砌上的H-多邊形問(wèn)題打下了基礎(chǔ)。
3 結(jié) 語(yǔ)
本文運(yùn)用H-三角形三元組(α,β,γ)的性質(zhì)和位級(jí)線理論,結(jié)合鋪砌點(diǎn)的分布特性,研究了[6.6.6]阿基米德鋪砌上H-三角形內(nèi)部H-點(diǎn)和邊界H-點(diǎn)的關(guān)系。證明了當(dāng)k取任意值時(shí),內(nèi)含k個(gè)H-點(diǎn)、邊界H-點(diǎn)數(shù)為3k+5的H-三角形存在,并且只有2種構(gòu)圖。
研究結(jié)論豐富了正六邊形阿基米德鋪砌的相關(guān)理論。2種構(gòu)圖的獲得對(duì)H-四邊形的同類問(wèn)題研究至關(guān)重要,能夠提供有效的論證方法和分類技巧。但是,關(guān)于H-多邊形的研究仍不是很全面,在今后的研究中,將利用鋪砌理論、分劃理論、凸集理論等方法,深入研究H-多邊形的邊界點(diǎn)問(wèn)題及相關(guān)應(yīng)用。
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