The paper gives new results related to the abduction process modeling. The results are based on a strategy that ensures, in minimum steps, the evidence necessary to deduce the correct hypothesis. An example that deals with two agents (robots), the Master and the Apprentice, that build a configuration of bricks, is inserted to exemplify the minimum length solution algorithm. The process of problem definition in this example involves both agents, and the cooperation between the agents is formalized in terms of decision trees. © 2011 IEEE.