Induction cooking pan bottom is concave - will this affect performance?
I don't think this should be an issue. The concave design is probably to reduce the amount of contact area between the cookware and the cook-top.

Having less contact area between the (hot) cookware and the cook-top keeps heat from flowing between the pan and the cook-top, resulting in:
- a cooler / safer cook top
- less wasted energy

For this very reason, those pans would not work well on a traditional electric stove where you want maximal heat flow (because the heat comes from the cook top, not the pan).