Fix latex warning
Fix latex warning

andre-senna/opencog,AmeBel/opencog,AmeBel/opencog,AmeBel/opencog,andre-senna/opencog,AmeBel/opencog,AmeBel/opencog,andre-senna/opencog,AmeBel/opencog,andre-senna/opencog,andre-senna/opencog,AmeBel/opencog,andre-senna/opencog,andre-senna/opencog