Assume you have 10,000 shs. ARU. =$63,000.
They are offering you 3,170 shs. of K X $19.11 = $60,579.
& 1,429 WTS let's value at $1.00 =$1,429.
for a total of $62,008.
In all standard takeover deals or sh. exchanges there is always room for arbitrage unless there is a mkt. expectation that the deal will be improved.
IMHO the mkt. is saying we have not seen the final bid or offer.
If we had, ARU would be trading between $6. & $6.10.