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Conversely, any rule of this sort, properly qualified by the conditions under which it applies, can be turned back into a summary statement of the logical equivalence that is involved in its application.  This mode of conversion a static principle and a transformational rule, that is, between a statement of equivalence and an equivalence of statements, is so automatic that it is usually not necessary to make a separate note of the "horizontal" versus the "vertical" versions.

Conversely, any rule of this sort, properly qualified by the conditions under which it applies, can be turned back into a summary statement of the logical equivalence that is involved in its application.  This mode of conversion between a static principle and a transformational rule, in other words, between a statement of equivalence and an equivalence of statements, is so automatic that it is usually not necessary to make a separate note of the "horizontal" versus the "vertical" versions of what amounts to the same abstract principle.

As another example of a STR, consider the following logical equivalence, that holds for any <math>Q \subseteq X</math> and for all <math>x \in X.</math>

As another example of an STR, consider the following logical equivalence, that holds for any <math>Q \subseteq X</math> and for all <math>x \in X.</math>

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