<condition>

The <condition> element is used often throughout MathML and is necessary to convey certain mathematical concepts. There is no direct equivalent in OpenMath, making translation impossible for certain expressions.

The <condition> element is used to define the `such that' construct in mathematical expressions. Condition elements are used in a number of contexts in MathML. They are used to construct objects like sets and lists by rule instead of by enumeration. They can be used with the forall and exists operators to form logical expressions. And finally, they can be used in various ways in conjunction with certain operators. For example, they can be used with an int element to specify domains of integration, or to specify argument lists for operators like min and max.

The example in figure 3.4 represents $\{\forall x \vert x<9: x<10\}$ and shows how the <condition> tags can be used in a MathML expression. This MathML expression has no OpenMath equivalent because OpenMath does not allow to specify any conditions on bound variables.

Figure 3.4: Use of <condition>

The <condition> tags are used in the following MathML elements: set, forall, exists, int, sum, product, limit, min and max. In all of these elements except limit, the use of <condition> tags makes translation impossible.

The case of limit is different because OpenMath does allow constraints to be placed on the bound variable; mainly to define the limit point and the direction from which the limit point is approached.