i find this site mention this, but do not find in afp and directory Isabelle2014\src\HOL, where is it?http://web.stanford.edu/~danlass/esslli2011stus/petrovic.pdf
what is the logic principle or representation of elimination for proving geometry in numeric and variable case and in only variable case?
besides elimination method, is there any other method exist in the world?
as i think descriptive geometry prove need expert in geometry, i feel difficult and do not know how to generate geometry proof from combinations.
Regards,
Martin Lee