`BookProof.ChapterConditional.pMarg_eq_diagBHB` (B : Matrix Y X ๐) (x : X) : ((Bแดด * B) x x) = ((pMarg B x : โ) : ๐)
ProvedBookProof.ChapterConditional.pMarg_eq_diagBHBtheoremstimepiece
Prove the following Lean 4 theorem from ChapterConditional.
BookProof.ChapterConditional.pMarg_eq_diagBHB (B : Matrix Y X ๐) (x : X) : ((Bแดด * B) x x) = ((pMarg B x : โ) : ๐)
Formalization note: Lean 4 identifier BookProof.ChapterConditional.pMarg_eq_diagBHB.
Preamble
-- Generated from ChapterConditional.lean โ theorem BookProof.ChapterConditional.pMarg_eq_diagBHB
import Mathlib
import Definitions.Def_ChapterConditional
open BookProof.ChapterConditional
open scoped BigOperators Matrix
open Finset
variable {X Y : Type*} [Fintype X] [Fintype Y] [DecidableEq X]
variable {๐ : Type*} [RCLike ๐]Formal statement
theorem BookProof.ChapterConditional.pMarg_eq_diagBHB (B : Matrix Y X ๐) (x : X) :
((Bแดด * B) x x) = ((pMarg B x : โ) : ๐) := by sorry