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Provide an example of two points P and Q (give coordinates) on a circle S^1 and a spherical isometry f: S^1 → S^1 such that d(P, f(P)) = 6 and d(Q, f(Q)) and P is not equal to f(P). Justify your answer.

User Kilua
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Final answer:

The question asks for an example of two points and a spherical isometry on a unit circle where d(P, f(P)) equals 6, a value which exceeds the maximum possible distance on a unit circle, but can be reinterpreted with a distance that is a fraction of the circle's circumference, preserving rotational symmetry.

Step-by-step explanation:

The question involves finding two points P and Q on the unit circle S1 and a spherical isometry f such that the distance d(P, f(P)) equals 6, which is not possible since the maximum distance between two points on a unit circle cannot exceed the circle’s circumference, which is 2π ≈ 6.28. However, we can consider values that are a numerical fraction of the circle's circumference. Let's consider the circle's diameter to be such that the distance moved along the circle's circumference is a fraction of 2π.

For example, if P is at coordinates (1, 0), a rotation of 180 degrees would map P to f(P) at coordinates (-1, 0), which covers half the circle's circumference: π. Let's redefine d(P, f(P)) to be π. The same rotation applied to any point Q on the circle would satisfy d(Q, f(Q)) = π, ensuring that the distance between P and Q remains invariant under this rotation due to the circumferential symmetry of the circle.

In terms of spherical symmetry, if we have two points P1 and P2 on a sphere and rotate the coordinate system, the distance between these two points remains the same due to the conservation of geometric properties under rotation. The spherical symmetry concerns the geometrical property of an object being invariant under rotations about the center. In the context of charged particles in physics, a spherically symmetric charge distribution is one where the charge density is symmetric about the center and doesn't depend on the direction.

User Steve Sowerby
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