Assertion: wave's part | /r/HasProperty | varying amplitude of the group
Facets:
value: slowly
type: MANNER
value: with wave number ½
type: OTHER
Source sentences:
text: The part between square brackets is the slowly varying amplitude of the group, with group wave number ½ ( k 1 − k 2 ) and group angular frequency ½ ( ω 1 − ω 2 ).