...I have been a resident of Portland for over 15 years. I worked for two years tutoring students for SAT, and ACT preparation at the Institute of College Information; a company formerly located on the Marylhurst University campus outside of Lake Oswego, OR. I also privately tutored students in Math during that time. (read more)
...I am a 68 year old retiree who enjoys working with high school students to improve their algebra and geometry skills. I have been doing on-line tutoring for 4 years and believe I’ve helped several students improve their grades while also keeping my own cognitive skills refreshed in retirement. I also have previous experience as a substitute teacher and teaching religious education. (read more)
...The following is a proof done by me on antisymmetric relations, followed by a shorter proof on set intersection of set differences. Set notation is displayed as "?" on this site, obscuring details
A relation R on a set A is antisymmetric if and only if R n R-1 ? {(a, a): a ? A}.
It will f... (read more)