I know that methods in a class should have high cohesion which roughly translates to having all the methods use all the instance variables directly or indirectly. I know that LCOM4 (Lack of cohesion)metric is useful for having a quantitative figure of how much cohesive the methods in a class are. A class with a LCOM4 value of 1 will be considered pretty good while a class with LCOM4 value of, say, 10 is considered a poorly designed class and this probably tells that we are better off decomposing the original class into 10 separate classes. All this is okay but what does the 4 signify in LCOM4 metrics?
LCOM4 is the fourth version of LCOM.
See http://www.aivosto.com/project/help/pm-oo-cohesion.html#LCOM4, under the subheading "Readings for LCOM4."