A restriction is a limit.
Restriction is a notion with etymological origin in the Latin restrictĭo . It's about the process and consequence of restricting . This verb , for its part, refers to limiting, adjusting, narrowing or circumscribing something.
For example: "The government announced a restriction on the import of chemical products with the aim of promoting national production" , "This literary contest does not set any restrictions regarding the length of the works" , "The organizers of the congress will establish a time restriction so that speakers do not go overboard with their presentations .
Scarcity restriction
It is common for authorities to establish restrictions on the purchase of certain products when there is a shortage . The objective is to prevent the products in question from being sold out and no longer available.
Suppose that, for different reasons, the amount of milk that is for sale in a country is small. To prevent hoarding by some, which would lead to a shortage for others, the government establishes a purchase restriction: each person can only purchase three liters of milk a week. This measure seeks to equitably distribute the available stock.
In some contexts, restriction implies a prohibition .
Other classes
Restriction, in general, always marks a limit. A young person who has to take an exam to enter a university is given a maximum of two hours to complete it. This means that there is a restriction to complete the exam: the candidate cannot take more than two hours to take the test. If you do not comply with the restriction, your evaluation is not accepted.
Genetics gives the name endonuclease or restriction enzyme to the one that has the ability to detect a certain sequence of nucleotides in a DNA molecule and then divide the DNA at that precise point, which is known as the target or restriction site . or in a not very distant part. To be recognized, these sites can have a number of base pairs ranging from four to six .
Restriction in mathematics
In the field of mathematics , it is called a restriction of one function to another that is defined in a subset of the domain of the initial one (the domain is, for its part, a set that brings together the values for which a function is defined), and that does not entail a change with respect to the values assigned to each element. It is correct to say that the function to which said restriction is applied is an extension of the resulting one.
Let's see below an example of this concept: if we have a set of people of all ages and another set of titles of movies that have been released in the last ten years, and a function relates them by graphing which is the favorite title of each person , we can apply a restriction that only takes into account individuals whose age group is between 30 and 40 years old, to focus on the tastes of said generation; This view has limits at both extremes, since it ignores people younger than 30 and older than 40, which is why the initial function can be considered an extension of it, because it shows a greater number of relationships (in fact, it shows all of them). ).
As we have seen so far, it is necessary to reduce the domain of a function to obtain one of its possible reductions. On the contrary, the term extension can also be used to talk about a function that contemplates a more numerous domain, although always with the condition of not varying the images of the first (also called range or field of values , the image is the set of the values that a given function can take).