Bashful C. Stupid-Butt said:
You mean Surrender/Stand, right? Because almost certainly it should be surrendered with Early Surrender.
Here are the EV's for no surrender, dealer ace, count 0, infinite deck. My intuition says that with early surrender against an ace, you should simply surrender anything where EV*9/13-4/13 < -0.5 => EV < (13/9)*(-0.5+4/13) = -0.278.
Hard 19 (S) : +0.278
Hard 18 (S) : -0.100
Hard 17 (S) : -0.478*
Hard 16 (H) : -0.517*
Hard 15 (H) : -0.480*
Hard 14 (H) : -0.440*
Hard 13 (H) : -0.397*
Hard 12 (H) : -0.351*
Hard 11 (H) : +0.143
Hard 10 (H) : +0.081
Hard 9 (H) : -0.066
Hard 8 (H) : -0.197
Hard 7 (H) : -0.310*
Hard 6 (H) : -0.304*
Hard 5 (H) : -0.279*
Likewise, against a dealer 10, it seems like you should surrender anything with an EV that's less than (13/12)*(-0.5+1/13) = -0.458.
Hard 19 (S) : +0.063
Hard 18 (S) : -0.178
Hard 17 (S) : -0.420
Hard 16 (H) : -0.540*
Hard 15 (H) : -0.504*
Hard 14 (H) : -0.466*
Hard 13 (H) : -0.425
Hard 12 (H) : -0.381
Hard 11 (D) : +0.180
Hard 10 (H) : +0.025
Hard 9 (H) : -0.153
Hard 8 (H) : -0.249
Hard 7 (H) : -0.319
Hard 6 (H) : -0.338
Hard 5 (H) : -0.313
If this method is correct, then I would calculate the following (again, the caveat being this is for infinite deck) :
7 vs A: Surrender/Hit
17 vs A: Surrender/Stand
AA vs A: Split
88 vs 10: Surrender/Split
11 vs 10: Double/Hit
33 vs A: Surrender/Hit
66 vs A: Surrender/Hit
77 vs A: Surrender/Hit
88 vs A: Surrender/Split
14 vs 10: Surrender/Hit
15 vs 10: Surrender/Hit
16 vs 10: Surrender/Hit