  Justification theory is an abstract unifying formalism that captures
semantics of various non-monotonic logics. One intriguing problem that has
received significant attention is the consistency problem: under which
conditions are justifications for a fact and justifications for its negation
suitably related. Two variants of justification theory exist: one in which
justifications are trees and one in which they are graphs. In this work we
resolve the consistency problem once and for all for the tree-like setting by
showing that all reasonable tree-like justification systems are consistent.
