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In some applications of connectedness, we shall define two fixed point theorems in connection with application of connectedness. Fixed point theorems are useful in obtaining the (unique) solutions of differential and integral equations.
Fixed Point: Let be a self mapping. A point is called a fixed point of , if . It may be noted that not every mapping has a fixed point.
Examples:
- Let
be defined by . Then each point is a fixed point.
- Let
be defined by . Then has no fixed point.
- Let
be defined by . Then has exactly one fixed point “0”.
Theorems:
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Let ![f: [0,1] to [0,1]](/topology/applications-connectedness/clip_image020.gif) be a continuous self mapping. Then there exist a point ![x belongs to [0,1]](/topology/applications-connectedness/clip_image022.gif) such that  .
- A contraction self mapping T defined on a complete metric space X has a unique fixed point.
Fixed Point Space: A space X is said to be a fixed point space, if every continuous self mapping on X has a fixed point. For example, is a fixed point space or in other words, we say that X has a fixed point property. Finally, we show that “a fixed point property” is a topological property.
Theorem: Let X and Y be homeomorphic spaces. Then each continuous mapping has a fixed point if and only if each continuous mapping has a fixed point.
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