Parallel and perpendicular lines form the foundation of geometry, impacting everything from architecture to computer graphics. Understanding their properties and relationships is crucial for mastering ...

Mathematics is distinguished from the sciences by the freedom it enjoys in choosing basic assumptions from which consequences can be deduced by applying the laws of logic. We call the basic ...

Lean companion of the Abstract Algebra I course, proving theorems in the notes. Note added in Feb 26 - With the help of Aristotle (https://aristotle.harmonic.fun/), many of the theorems proved in ...