Theorems · Theorem · general topology
Circle.hasBasis_centeredArc_div_two_pow
(nhds 1).HasBasis (fun x => True) fun n => Circle.centeredArc (Real.pi / 2 ^ (n + 1))
The centered arcs centeredArc (π / 2 ^ (n + 1)) form a neighborhood basis at 1.
This basis is useful because multiplying two sufficiently small arcs stays inside an earlier arc.
- Cited by
- 1 results in Mathlib
- Foundations
- Depth 211 from the axioms · uses propext, Classical.choice, Quot.sound
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Cites32
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Cited by1
Results whose statement or proof uses this declaration.
- Circle.eq_one_of_forall_pow_mem_centeredArc_pi_div_twoproof · cited by 0