I think that [1] and [2] are just plain incorrect.
[3] follows the syntactic structure a bit too closely for my taste.
I prefer [4] and have made it the standard of the AMR Corpus for the time being.
A special predicate such as x-or-more with basically the same meaning as at-least is also conceivable.
I found inconsistencies in the AMR corpus for expressions of the form <quantity> or more such as 300 grams or more of heroin:
[1] (or :op1 (q / quantity ...) :op2 more) [2] (or :op1 (q / quantity ...) :op2 (more :compared-to q)) [3] (or :op1 (q / quantity ...) :op2 (more-than :op1 q)) [4] (at-least :op1 (q / quantity ...))
I think that [1] and [2] are just plain incorrect. [3] follows the syntactic structure a bit too closely for my taste. I prefer [4] and have made it the standard of the AMR Corpus for the time being. A special predicate such as x-or-more with basically the same meaning as at-least is also conceivable.