Eraserman,I think 'may' is a tricky word these days. In current English usage it is often used in the same way as 'might' - implying a degree of possibility.
"It may/might rain today."
It is also used interchangeably with 'can'.
"You may/can go to the ball."
Personally, I think in the preamble 'may' is used in the sense of 'can'.
(Although, interestingly, we are not being asked to show how we have linked the pairs - for instance, by listing them under the grid.)