Block_of_a_ring
Peirce decomposition
Decomposition method in algebra
In ring theory, a Peirce decomposition /ˈpɜːrs/ is a decomposition of an algebra as a sum of eigenspaces of commuting idempotent elements. The Peirce decomposition for associative algebras was introduced by Benjamin Peirce (1870, proposition 41, page 13). A similar but more complicated Peirce decomposition for Jordan algebras was introduced by Albert (1947).