Calkin algebra
the quotient of the ring of bounded linear operators on the separable infinite‐dimensional Hilbert space by the ideal compact operators
en-GB/kælkɪn ˈæld͡ʒɪbɹə/
en-US/ˈkælkɪn ˈæld͡ʒəbɹə/
the quotient of the ring of bounded linear operators on the separable infinite‐dimensional Hilbert space by the ideal compact operators