Theorem: Matroid.parallelExtend_dual (Matroid/Constructions/ParallelExtension.lean)

State before:
α : Type u_1
inst✝ : DecidableEq α
M✝ M' : Matroid α
e✝ f✝ : α
M : Matroid α
e f : α
⊢ (M.parallelExtend e f)✶ = M✶.seriesExtend e f
Tactic:
rw [seriesExtend, dual_dual]
State after:
no goals