Journal of Human-Robot Interaction, Vol. 2, No. 1, 2013, Pages 152-171, DOI 10.5898/JHRI.2.1.McColl Meal-Time with a Socially Assistive Robot and Older Adults at a Long-term Care Facility Derek McColl and Goldie Nejat 1,2 Autonomous Systems and Biomechatronics Laboratory, Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada Toronto Rehabilitation Insti...

We prove that every perfect torsion theory for a ring R is differential (in the sense of [2]). In this case, we construct the extension of a derivation of a right R-module M to a derivation of the module of quotients of M . Then, we prove that the Lambek and Goldie torsion theories for any R are differential.