List of possible triangles (redshift bin combinations) with condition z_i < z_j and z_i < z_k when 4 redshift bins are available. An angular frequency combination satisfying ℓ₁ ≤ ℓ₂ ≤ ℓ₃ is chosen. Note that the redshift indices and the angular frequencies are linked in pairs due to the definition of the tomographic bispectrum (14). In this paper a default of 10 redshift bins is assumed.