FEYN CALC SYMBOL

Isolate


substitutes abbreviations KK[i] for all Plus[...] (sub-sums) in expr. The inserted KK[i] have head HoldForm. Isolate[expr, varlist] substitutes KK[i] for all subsums in expr which are free of any occurence of a member of the list varlist. Instead of KK any other head or a list of names of the abbreviations may be specified with the option IsolateNames.