OAI/GroupTheory/PolycyclicRecognition/Algebra/SimplyConnectedRetraction.lean

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2 declarations, 0 contain sorry, 0 declared as axioms

Simple connectivity of a split kernel

A continuous retraction preserves simple connectivity. A group quotient with a normalized continuous section retracts onto its actual kernel.

  1. theorem OAI.PolycyclicRecognition.simplyConnectedSpace_of_continuous_retraction line 17
  2. theorem OAI.PolycyclicRecognition.simplyConnectedSpace_kernel_of_section line 37