MHp for constraints= ~degreesmix. Similar to InitErgmProposal.CondDegree, except that
the toggle is proposed only if the mixing matrix of degrees is preserved before and after the toggle.
ergm:::.formatProposalsHtml(ergm:::.buildProposalsList(proposal="CondDegreeMix"))
ergmProposal for index of proposals currently visible to the package.
ergm:::.formatTermKeywords("ergmProposal", "CondDegreeMix", "subsection")