MHB Why Does γ(t) = z(1-t) Represent the Same Curve in Reverse?

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The discussion centers on understanding why the expression γ(t) = z(1-t) represents the same curve as z(t) but in reverse. It highlights that by substituting t with 1-t in the linear interpolation formula z(t) = z0 + (z1 - z0)t, one can derive the reversed expression. Conceptually, the mapping t to 1-t reverses the direction of traversal along the curve, as it swaps the endpoints of the interval [0,1]. This means that while z(t) traces the curve from z0 to z1, γ(t) traces it from z1 back to z0. Understanding this relationship is crucial for grasping the topology of complex numbers as discussed in the referenced text.
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I am reading "Complex Analysis for Mathematics and Engineering" by John H. Mathews and Russel W. Howell (M&H) [Fifth Edition] ... ...

I am focused on Section 1.6 The Topology of Complex Numbers ...

I need help in fully understanding a remark by M&H ... made just after Example 1.22 ...

Example 1.22 (including some post-Example remarks ...) reads as follows:View attachment 7342
View attachment 7343In the above text from Mathews and Howell we read the following in remarks made after the presentation of the example:

" ... ... Note that $$\gamma (t) = z ( 1-t )$$, ... ... "Can someone please explain how/why $$\gamma (t) = z ( 1-t )$$ ... ... ?

Peter
 
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You could just start from $z(t) = z_0 + (z_1 - z_0)t$, replacing $t$ by $1 - t$ and work out the algebra to get the expression $z_1 + (z_0 - z_1)t$. Alternatively, you can view this conceptually. The map $t \mapsto 1 - t$ from $[0,1]$ to $[0,1]$ maps $0$ to $1$ and $1$ to $0$, so $z(1-t)$ traces $C$ in the opposite direction that $z(t)$ does.
 
We all know the definition of n-dimensional topological manifold uses open sets and homeomorphisms onto the image as open set in ##\mathbb R^n##. It should be possible to reformulate the definition of n-dimensional topological manifold using closed sets on the manifold's topology and on ##\mathbb R^n## ? I'm positive for this. Perhaps the definition of smooth manifold would be problematic, though.

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