I guess, your context is definition of limits

In mathematics , a limit is the value that a function or sequence "approaches" as the input or index approaches some value . [1] Limits are essential to calculus (and mathematical analysis in general) and are used to define continuity , derivatives , and integrals .

The concept of a limit of a sequence is further generalized to the concept of a limit of a topological net , and is closely related to limit and direct limit in category theory .

In formulas, a limit is usually written as

lim n → c f ( n ) = L

and is read as "the limit of f of n as n approaches c equals L ". Here "lim" indicates limit , and the fact that function f ( n ) approaches the limit L as n approaches c is represented by the right arrow (→), as in

f ( n ) → L   .