Assume Alt(exh(AvB > C)) = { exh(A > C), exh(B > C) } = { (A > C) & ~(B > C), (B > C) & ~(A > C) }.

Then exh(exh(AvB > C)) = (AvB > C) & ~[(A > C) & ~(B > C)] & ~[(B > C) & ~(A > C)].

~[(A > C) & ~(B > C)] & ~[(B > C) & ~(A > C)] is equivalent to (A > C) <-> (B > C).

Assuming that AvB > C entails (A > C) v (B > C), it follows that exh(exh(AvB > C)) entails (but is not equivalent to) A > C and B > C.

In your examples, one or both of A and B in the antecedent is complex, which might introduce some more alternatives, but I'd expect the above entailment to remain.

As far as I can tell, this also gets (9)/(10) right.

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Still assuming your calculation is correct, I have a query. Take scenario 1 in the paper (Both children are on the right and the seesaw is balanced) and evaluate the following:

(3a') If Blue or both of them were on the left, then the seesaw would be unbalanced.

In that scenario I feel like (3a') is false, because if Blue was on the left, the seesaw would be balanced! But if exh(exh(Av(A&B)>C)) is equivalent to A&B>C, then we should expect (3a') to be true, since if both children were on the left, it would indeed be unbalanced.

Perhaps this is also relevant. In the paper, exhaustifying Av(A&B) to obtain (A&-B)v(A&B) was forcing a dilemma on the friends of the exhaustification. They get the (3a)-(4a)-(4b) trio right, but then they could not get the (9a)-(10a)-(10b) trio right. I cannot tell whether double exhaustification is helping with that or not. Is it?

Also thank you so much for the discussion!]]>

Could you tell more how you thought double exhaustification would help?]]>

I believe Romoli, Santorio and Wittenberg gave a semantic explanation for these cases in terms of questions under discussion and interpretation of negation. Perhaps yours is a pragmatic version of that:

https://semanticsarchive.net/Archive/mEwMmQzN/Alternatives_in_counterfactuals__third_round_%20(1)%20-%20Eva%20Wittenberg.pdf.

I explicitly argued against the exclusivity implicature in antecedents in a separate paper by manipulating cases similar to CZC:

https://link.springer.com/article/10.1007/s10988-022-09360-3; https://philpapers.org/go.pl?aid=GNGCHA]]>