Arlington County has an extensive network of bicycle infrastructure, including 50 miles of shared-use off-street trails. These multi-use trails are generally 10 feet wide with a solid yellow line striped down the middle to separate users.
Constructive mathematics. Idea. Broadly speaking, constructive mathematics is mathematics done without the principle of excluded middle (or other principles, such as the full axiom of choice, that imply it).
The difference between the two is the type of logic used to correlate the points of proof. Essays on mathematics make use of deductive reasoning to work out the mathematical thesis or theorem being developed while scientific writing relies on the inductive organization of data to prove its premised statement.