Dear all,

I have question but cannot explain without providing some context first:

I want to calculate how many policy-connected coalitions between 7 parties are possible. I have positions on an one-dimensional scale for each party and I have sorted the parties on the positions (it is sorted from extreme left to extreme right, hence using a left-right scale). A policy-connected coalition consists of parties that are connected on this left-right scale, hence there cannot be a party outside the coalition that is in-between two parties in the coalition on the left-right scale. My question is: how do a make a matrix that excludes those coalitions that are not policy-connected.

I made a matrix with each combination of 0 (out of coalition) and 1 (in coalition), for 7 parties.

a <- expand.grid(rep(list(c(0,1)),7))

a gives all possible coalitions between these 7 parties.

Now I want to exclude those rows with coalition that are not policy-connected.

Hence: this one should be out, because the fifth party is not in.

0 1 1 1 0 1 1

And this one should be in,

0 0 0 1 1 1 1.

Hope this is clear and that someone has a good suggestion.

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