psumSum — Mathlib

English

Combine two equivalences by feeding PSum in the domain and Sum in the codomain; form a new equivalence between PSum α1 β1 and Sum α2 β2.

Русский

Сочетаем два эквивалентности по оси PSum в области и Sum в кодобе, получая новую эквив between PSum α1 β1 и Sum α2 β2.

LaTeX

$$def psumSum {α₁ β₁} (ea : α₁ ≃ α₂) (eb : β₁ ≃ β₂) : α₁ ⊕' β₁ ≃ α₂ ⊕ β₂$$

Lean4

/-- Combine two `Equiv`s using `PSum` in the domain and `Sum` in the codomain. -/
def psumSum {α₂ β₂} (ea : α₁ ≃ α₂) (eb : β₁ ≃ β₂) : α₁ ⊕' β₁ ≃ α₂ ⊕ β₂ :=
  (ea.psumCongr eb).trans (psumEquivSum _ _)

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