Evolutes and Involutes of Frontals in the Euclidean Plane

Demonstratio mathematica

article

Tomonori Fukunaga¹  Masatomo Takahashi² 

[1] KYUSHU SANGYO UNIVERSITY FUKUOKA 813-8503;MURORAN INSTITUTE OF TECHNOLOGY

关键词: evolute;    involute;    frontal;    Legendre curve;    inflection point;   

DOI  :  10.1515/dema-2015-0015

学科分类：外科医学

来源: De Gruyter

【 摘 要 】

We have already defined the evolutes and the involutes of fronts without inflection points. For regular curves or fronts, we can not define the evolutes at inflection points. On the other hand, the involutes can be defined at inflection points. In this case, the involute is not a front but a frontal at inflection points. We define evolutes of frontals under conditions. T he definition is a generalisation of both evolutes of regular curves and of fronts. By using relationship between evolutes and involutes of frontals, we give an existence condition of the evolute with inflection points. We also give properties of evolutes and involutes of frontals.

【 授权许可】

CC BY