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advanced_tools:topology:homotopy [2018/03/24 14:46] jakobadmin ↷ Links adapted because of a move operation |
advanced_tools:topology:homotopy [2018/04/12 15:33] (current) jakobadmin [Concrete] |
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====== Homotopy ====== | ====== Homotopy ====== | ||
+ | |||
+ | |||
+ | <tabbox Intuitive> | ||
+ | |||
+ | <note tip> | ||
+ | Explanations in this section should contain no formulas, but instead colloquial things like you would hear them during a coffee break or at a cocktail party. | ||
+ | </note> | ||
+ | | ||
+ | <tabbox Concrete> | ||
+ | |||
+ | ** Definition ** | ||
+ | Two maps $f$ and $g$ are called **homotopic**, denoted by $f \tilde g$ if we can continuously transform them into each other. (See the example below). | ||
+ | |||
+ | Source: page 14 in https://arxiv.org/pdf/hep-th/0403286.pdf | ||
+ | |||
+ | ---- | ||
+ | **Example ** | ||
+ | |||
+ | --> Equivalence of $f(x)=x$ and $g(x)=$const.# | ||
+ | |||
+ | The two maps | ||
+ | |||
+ | $$ \mathbb{R}^n \to \mathbb{R}^n : f(x)= x $$ | ||
+ | and | ||
+ | $$ \mathbb{R}^n \to \mathbb{R}^n : g(x)= x_0 = \text{const} $$ | ||
+ | |||
+ | are homotopic, because we can define | ||
+ | |||
+ | $$ F(x,t) = (1-t)x+tx_0 ,$$ | ||
+ | |||
+ | which continuously transforms $f(x)=F(x,0)$ into $g(x)=F(x,1)$. | ||
+ | |||
+ | |||
+ | <-- | ||
+ | |||
+ | <tabbox Abstract> | ||
+ | |||
+ | <note tip> | ||
+ | The motto in this section is: //the higher the level of abstraction, the better//. | ||
+ | </note> | ||
<tabbox Why is it interesting?> | <tabbox Why is it interesting?> | ||
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<cite>http://www.dartmouth.edu/~dbr/topdefects.pdf</cite> | <cite>http://www.dartmouth.edu/~dbr/topdefects.pdf</cite> | ||
</blockquote> | </blockquote> | ||
- | |||
- | <tabbox Layman> | ||
- | |||
- | <note tip> | ||
- | Explanations in this section should contain no formulas, but instead colloquial things like you would hear them during a coffee break or at a cocktail party. | ||
- | </note> | ||
| | ||
- | <tabbox Student> | ||
- | ** Definition ** | ||
- | Two maps $f$ and $g$ are called **homotopic**, denoted by $f \tilde g$ if we can continuously transform them into each other. (See the example below). | ||
- | Source: page 14 in https://arxiv.org/pdf/hep-th/0403286.pdf | ||
- | <tabbox Researcher> | ||
- | |||
- | <note tip> | ||
- | The motto in this section is: //the higher the level of abstraction, the better//. | ||
- | </note> | ||
- | |||
- | | ||
- | <tabbox Examples> | ||
- | |||
- | --> Equivalence of $f(x)=x$ and $g(x)=$const.# | ||
- | |||
- | The two maps | ||
- | |||
- | $$ \mathbb{R}^n \to \mathbb{R}^n : f(x)= x $$ | ||
- | and | ||
- | $$ \mathbb{R}^n \to \mathbb{R}^n : g(x)= x_0 = \text{const} $$ | ||
- | |||
- | are homotopic, because we can define | ||
- | |||
- | $$ F(x,t) = (1-t)x+tx_0 ,$$ | ||
- | |||
- | which continuously transforms $f(x)=F(x,0)$ into $g(x)=F(x,1)$. | ||
- | |||
- | |||
- | <-- | ||
- | |||
- | |||
- | |||
- | <tabbox FAQ> | ||
- | | ||
- | <tabbox History> | ||
</tabbox> | </tabbox> | ||