Velocity of A with respect to C |
= | Velocity of A with respect to B |
+ | Velocity of B with respect to C |

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reduction factor |

where

reduction factor =

1 + (Velocity of A with respect to B/c) x (Velocity of B with respect to C/c)

Here's how the reduction factors for boosting light are computed. Take the simple case of composing 0.1c with c. the reduction factor is

1 + (0.1c/c)x(c/c) = 1 + (0.1)x(1) = 1.1

The other cases in the main text are computed correspondingly.