Define a new big operator in ConTeXt

Question

I would like to replace the sum symbol by a big plus as Pedro G. Mattos wanted to do here How can I define a big plus operator that works like \bigcup?.

In the wiki I found that the command I should use is \definemathsymbol. However I am confused about how to adapt the symbol for both inline and display maths.

A solution might exactly be https://wiki.contextgarden.net/Product_integral but I do not get it and I do not want to use various commands such as prodi, PRODI... but only the sum one. Is it possible?

The code is very basic.

\starttext
    Solve for \m{n} the following:
    \startformula
        \sum_{k=0}^n k = 6
    \stopformula
    {\bf Hint:} \m{\sum_{k=0}^2 k = 3}
\stoptext

If you solve the problem, an answer to replace prod by a big times would also be appreciated.

Henri Menke · Accepted Answer · 2019-01-01T23:01:33.933

The is no such things as a “big plus“ in Unicode. However, there is a big times as per your second request.

\starttext
    Solve for \m{n} the following:
    \startformula
        \bigtimes_{k=0}^n k = 6
    \stopformula
    \bold{Hint:} \m{\bigtimes_{k=0}^2 k = 3}
\stoptext

You can make your own big plus by just scaling the regular plus symbol. This is typographically not very consistent because it also scales the line width.

\define\bigplus{%
  \mathop{%
    \mathchoice
      {\dobigplus{2000}}%
      {\dobigplus{1500}}%
      {\dobigplus{ 900}}%
      {\dobigplus{ 700}}%
  }%
}

\define[1]\dobigplus{%
  \vcenter{\hbox{\scale[scale=#1]{$+$}}}%
}

\starttext
    Solve for \m{n} the following:
    \startformula
        \bigplus_{k=0}^n k = 6
    \stopformula
    \bold{Hint:} \m{\bigplus_{k=0}^2 k = 3}
\stoptext

Define a new big operator in ConTeXt

1 Answers1