If one has ever used an XML editor, one knows the frustration of you having to do the bulk of the work locating mismatched or unclosed <> tags. Let us view tags as delimiters on sets and subsets. Consider the case where the XML editor has checked all beginning and ending tags and found an equal number of beginning and endint tags of a given name: a, b, etc. Nevertheless, even though we have an equal number of and tags and and tags is wrong syntactically because the "set" "intersects" with the "set" non-trivially, yet neither set is a proper subset of the other. Certainly, if a computer algebra system such as Maple can determine set overlaps like this, then

In Math Mode in a Maple worksheet, how do I type something such as L := [1, 2, "abc", "a", 7.0, infinity]; for x in L do if type(x, 'string') then print(x); break end if end do on multiple lines? Also, please show me in the online Help menu the explanation for how one makes such line breaks without setting off execution. I got Maple last August. I have searched the online Help menu for any mention of a line break but have not found it. Thank you.

How do I locate a particular theorem in Linear Algebra that I need for my research? I have been to conferences which seriously discussed a unified and universal bank of all known math theorems. Theoretically, all proven math theorems could be connected logically: A implies B. But, in reality, most proven math theorems are scattered throughout the literature. I have no access to a university with math journals. I might be able to do inter-library loan at my local community county college here in the United States. But, that may take a long time. I have no paid job. My earned income is only from social security disability.

How do I get anything to work with the differential algebra package with(diffalg)? Maple does not recognize its own commands and then makes things worse by crashing my computer. I've had to pull the plug on my computer at least twice. For instance, whenever I try to type "differential_ring" as soon as I type the underscore, Maple puts me into a subscript mode. Also, there seem to be TWO packages of commands for everything: e.g. with(linalg) and with(LinearAlgebra) with(diffalg) and with(DifferentialAlgebra) which overlap tremendously! Also, sometimes [[a,b],[c,d]] is recognized as a matrix and sometimes it is not. Changing it to

Hi, again. Another applied problem arose today which requires me to compute all the roots of a polynomial with real coefficients. The degree needs to be left arbitrary. I only see vague references on the internet to the very abstract, symbolic "formula" (if one wishes to call it that) for all the roots of a polynomial in terms of siegel (siegal? seagel?) elliptic modular functions. No one ever seems to try to use it. The only person I know who ever wrote out the formula was Hiroshi Umemura, professor from Nagoya University in Japan. I actually contacted him once, back in 1994. But