Selective control means the target comparison is true while the neighbor comparison is false. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
The target transition matches
The pulse 6 equals the target gap 6, so the target response is checked true.
6=6
The neighbor transition stays off
The same pulse 6 does not equal the neighbor gap 4, so the neighbor response is checked false.