👉 Invariable is a concept in mathematics and analysis, particularly in functional analysis. It refers to an element of a Banach space that satisfies certain properties without any functionally dependent elements. In other words, it's a property that allows us to define a norm on a vector space by using only the linear maps between the elements of the space itself, rather than relying on functions. Invariance is a special case of invariable where the element under consideration is an inner product or norm. This concept