The police arrested and beat up [some] demonstrators

[azz]

a. The police arrested and beat up demonstrators.
b. The police arrested and beat up some demonstrators.

To me it seems that in (b) the demonstrators who were arrested were then beaten up. In (a) that might have been the case, but it is far more likely that the police arrested some and beat up others (with some possible overlap).

I think these two sense but doesn't really sound natural (unless the speaker doesn't know which of the two things the police did):

c. The police arrested or beat up demonstrators.
d. The police arrested or beat up some demonstrators.

Am I correct in my analysis? I am trying to apply logic to language. I know that I am on slippery ground!

 

[Tarheel]

Oddly, you don't seem to know what your sentences mean.

a. The police arrested and beat up demonstrators.
The police arrested and beat up an undetermined number of demonstrators. (They both arrested them and beat them up.)

b. The police arrested and beat up some demonstrators.
Do you think "some" changes the meaning of the sentence?

c. The police arrested or beat up demonstrators.
Well, they did one of two things, but we're not sure which one.

d. The police arrested or beat up some demonstrators.
Again, they did one of two things, but we're not sure which one.

 

[jutfrank]

Am I correct in my analysis?

I don't think so, no.

 

[emsr2d2]

Did you write the original two sentences yourself? If so, why? Good writers don't write things that are intentionally ambiguous. If there were two separate sets of demonstrators, we would write:

The police arrested some demonstrators and beat up some others.