1. <animation> "Concepts" section directs reader to discussion about interpolatin animation curves in the Programming Guide chapter, but there is also info about animation curves in <sampler> element. Shd reference that, also. E.g., "For more information about animation curves, see <sampler>."
2. Explanation of child element requirements could be more exact. Current text reads:
The child elements follow these rules:
• The <animation> element must contain at least one of the following:
• <sampler> and <channel>
• <sampler> and <channel> must always be used together.
The <animation> element must contain at least one of either or both of the following:
• One or more <animation>
• One or more <sampler> and one or more <channel>