# Question: What Is Well Defined In Math?

## What is meant by well defined?

1: having clearly distinguishable limits, boundaries, or features a well – defined scar. 2: clearly stated or described well – defined policies.

## How do you show well defined?

So to say that something is well – defined is to say that all three things are true. When we write f:X→Y we say three things:

1. f⊆X×Y.
2. The domain of f is X.
3. Whenever ⟨x,y1⟩,⟨x,y2⟩∈f then y1=y2. In this case whenever ⟨x,y⟩∈f we denote y by f(x).

## Are all functions well defined?

All functions are well – defined; but when we define a function, we don’t always know (without doing some work) that our definition really does give us a function. We say the function (or, more precisely, the specification of the function ) is ‘ well – defined ‘ if it does.

## Is well defined the same as one to one?

Surjectivity simply means image and codomain are the same. Well – definition only gives you a function. It allows not all points of the codomain to be hit by the function, as well as it allows many points to be mapped on the same image point. Both are not allowed for a one-to-one bijection.

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## What is the example of well-defined?

A set is well – defined if there is no ambiguity as to whether or not an object belongs to it, i.e., a set is defined so that we can always tell what is and what is not a member of the set. Example: C = {red, blue, yellow, green, purple} is well – defined since it is clear what is in the set.

## What is another word for well-defined?

precise, unambiguous, straightforward, distinct, clear-cut, explicit, transparent, apparent, audible, comprehensible, intelligible, legible, lucid, obvious, plain, sharp, understandable, lucent, graspable, spelled out.

## What is a well defined limit?

A limit is well – defined if and only if both the left-sided limits and the right-sided limits exist and are finite. In this case, the right-sided limit exists and is 0, since as, then the function approaches 0. On the other hand, the left-sided limit does not exist.

## What does Defined mean in math?

So simply put, if a function is said to be defined for a certain range, then that means the function will provide a value for that range.

## What does Defined mean?

: to explain the meaning of (a word, phrase, etc.): to show or describe (someone or something) clearly and completely.: to show the shape, outline, or edge of (something) very clearly.

## What is a well defined problem?

Well – defined ( well -structured) problems are those that contain a clear specification of three elements of the problem space: the initial state (the problem situation), the set of operators (rules and strategies) to solve the problem, and the goal state (the solution).

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## What does a function being defined mean?

A function is more formally defined given a set of inputs X (domain) and a set of possible outputs Y (codomain) as a set of ordered pairs (x,y) where x∈X (confused?) and y∈Y, subject to the restriction that there can be only one ordered pair with the same value of x.

## What do you call a set with no elements?

In mathematics, the empty set is the unique set having no elements; its size or cardinality (count of elements in a set ) is zero. Some axiomatic set theories ensure that the empty set exists by including an axiom of empty set, while in other theories, its existence can be deduced.

## What makes a well defined function?

A function is well – defined if it gives the same result when the representation of the input is changed without changing the value of the input. For instance, if f takes real numbers as input, and if f(0.5) does not equal f(1/2) then f is not well – defined (and thus not a function ).

## How do you check if a map is well defined?

Let ϕ:S/R→T be a mapping such that: ϕ([[x]]R)=f(x) Then ϕ:S/R→T is well – defined if and only if: ∀(x,y)∈R:f(x)=f(y)

## Is a well defined collection of objects?

Definition: A set is a well – defined collection of distinct objects. The objects of a set are called its elements. If a set has no elements, it is called the empty set and is denoted by ∅. 