Re : Problems with sum

Hi Bartolomé,
 
 About the solution of the bug, &sum is an operator so must be in a <mo>, so replacing it by <mi> is not a good thing. For the change of size when the sum is inserted in a line of text, I don't believe it is a bug but that it is normal to have the operator symbol resized according to the context. If the user wants to have the operator to be large, I think it would put it out of a text paragraph.
 In fact, I believe there are special attributes to force the way the symbol is displayed, I don't look in detail but I remember that in the MathML 2.0 specification, they talk about attributes such as largeop, or displaystyle as you mentionned. If no attribute are specified, the interpretation is let to the software. For example, Firefox display a small sum symbol if there is no attribute. I think in this case, the right way is to do as Amaya does, I mean to choose the size of the operator according to the context. So I don't know it is a bug, just a different behaviour that, anyway, is not precised in MathML specification.
 
 Fred