👉 Invariance is a concept in physics and mathematics that refers to properties of a mathematical object or system that remain unchanged under an infinitesimal change. In other words, if we vary the variables in a formula, the result will not depend on those variables at all. For example, consider the function f(x) = x^2 + 3x - 5. If we change one variable (say x), say to x' = x/2, then f(x') = (x