Endomorphism ring Summable endomorphisms Let ๐ be a vector space over ๐ and {๐ฅ๐}๐โ๐ผ โEndโก๐ be a family of linear operators. We say{๐ฅ๐}๐โ๐ผ is summable iff for any ๐ฃ โ๐, ๐ฅ(โ)๐ฃ has finite support, #m/def/linalg and thence1 โ๐โ๐ผ๐ฅ๐:๐โ๐๐ฃโฆโ๐โ๐ผ๐ฅ๐๐ฃ #state/tidy | #lang/en | #SemBr Footnotes 1988. Vertex operator algebras and the Monster, ยง2.1, p. 49 โฉ