Lensing kernels for X = Y = T, left column, X = Y = E, middle, and X = B,Y = E, right, for two different values of the multiple number of the lensed signal, , top to bottom. The color scale shows the logarithm of the kernel elements and ranges from dark blue ~ 10^-15 to ~1, dark red. The solid-line contours show the best achievable precision of the estimated lensed spectrum, that can be obtained if the bandwidths of the E and/or Φ unlensed spectra are truncated to ℓ^E and ℓ^Φ. The contours range from 25% to 0.01% from left to right. The precision is computed with respect to the lensed multipoles calculated with .