rec-sum1 MathML 2 Recomendation Content/SequencesAndSeries/sum ../../../Content/TheoryOfSets/cartesianproduct/rec-cartesianproduct2 ../../../Content/SequencesAndSeries/sum/sum2 $\sum_{x=a}^b f(x)\sum_{x\in B} f(x)$ <math xmlns="http://www.w3.org/1998/Math/MathML"> <apply> <sum/> <bvar> <ci> x </ci> </bvar> <lowlimit> <ci> a </ci> </lowlimit> <uplimit> <ci> b </ci> </uplimit> <apply> <ci type="fn"> f </ci> <ci> x </ci> </apply> </apply> <apply> <sum/> <bvar> <ci> x </ci> </bvar> <condition> <apply> <in/> <ci> x </ci> <ci type="set"> B </ci> </apply> </condition> <apply> <ci type="fn"> f </ci> <ci> x </ci> </apply> </apply> </math>