Coalition Formability Semantics with Conflict-Eliminable Sets of
  Arguments
  We consider abstract-argumentation-theoretic coalition formability in this
work. Taking a model from political alliance among political parties, we will
contemplate profitability, and then formability, of a coalition. As is commonly
understood, a group forms a coalition with another group for a greater good,
the goodness measured against some criteria. As is also commonly understood,
however, a coalition may deliver benefits to a group X at the sacrifice of
something that X was able to do before coalition formation, which X may be no
longer able to do under the coalition. Use of the typical conflict-free sets of
arguments is not very fitting for accommodating this aspect of coalition, which
prompts us to turn to a weaker notion, conflict-eliminability, as a property
that a set of arguments should primarily satisfy. We require numerical
quantification of attack strengths as well as of argument strengths for its
characterisation. We will first analyse semantics of profitability of a given
conflict-eliminable set forming a coalition with another conflict-eliminable
set, and will then provide four coalition formability semantics, each of which
formalises certain utility postulate(s) taking the coalition profitability into
account.
