[2] In addition, some parts of theoretical computer science can be thought of as using non-classical reasoning, although this varies according to the subject area.
However, in contrast, some computerized proof methods may not use classical logic in the reasoning process.
[5] A few other authors have adopted the main distinction between deviation and extension in non-classical logics.
[6][7][8] John P. Burgess uses a similar classification but calls the two main classes anti-classical and extra-classical.
[8][9] Additionally, one can identify a variations (or variants), where the content of the system remains the same, while the notation may change substantially.