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Part BCSIR NET December 2024one-interior-point-fixes-which-side-maps-in

One interior point fixes which side maps in

Consider the half planes R₊ = {z = x + iy } and R₋ = {z = x + iy }, and the fractional linear transformations and . Let disc 𝔻 = { : |z| < 1}. Which of the following statements is true?

  1. A. and conformally map R₊ and R₋ respectively, onto the disc 𝔻
  2. B. and conformally map R₋ and R₊ respectively, onto the disc 𝔻
  3. C. and conformally map the disc 𝔻 onto, respectively R₊ and R₋
  4. D. and conformally map the disc 𝔻 onto, respectively R₋ and R₊

You have the answer. Trap Analysis is why the other three were written.

Not a worked solution repeated four times — the specific reasoning error each wrong option was built to reward.

See pricing

50 are analysed free — try those first.

Related counterexample: ℂ and the unit disc are biholomorphic (both are simply connected)

More on this topic

The chapter behind this: Conformal maps and Möbius transformations — free to read

From Zeros and MappingsConformal maps, Möbius transformations, Schwarz lemma

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