Monotonicity

https://en.wikipedia.org/wiki/Monotonic_function https://en.wikipedia.org/wiki/Monotonicity_of_entailment

A monotonic or monotone function is a function between ordered sets that preserves or reverses the given order.

• a ⊑ b -> f(a) ⊑ f(b) preserves the ordering

• a ⊑ b -> f(a) ⊒ f(b) reverses the ordering

Monotonicity: having the property of never increasing or never decreasing as the values of the independent variable (or the subscripts of the terms) increase.