The customary numerical solution to the *x*-domain forms of the equations
in Tables .3 and .4 is arrived at by splitting.
That is, you march forward a small -step alternately
with the two extrapolators

(18) | ||

(19) |

(20) |

Migrations that include the lens equation
are called *depth * migrations.
The term is often omitted,
giving a *time * migration.

Observe that the diffraction parts of Tables .3 and .4 are the same.
Let us use them and equation (19) to
define a table of diffraction equations.
Substitute for *i k*_{x} and
clear from the denominators to
get Table .5.

10/31/1997