lean_workbook_plus_12543
ProvedIsn't the triangle inequality just for I z1 I + I z2 I I z1 + z2 I ?
Preamble
import Mathlib.Analysis.Complex.Basic
Formal statement
theorem lean_workbook_plus_12543 (z1 z2 : ℂ) : ‖z1‖ + ‖z2‖ ≥ ‖z1 + z2‖ := by sorry
Source