# Complementarity¶

Complementarity is a corollary of duality as applied to elements, functions, and dichotomies, all of which describe how and why duals are the most compatible types.

## Complementary IM elements¶

Quadra values comprise two pairs of complementary elements, which must be either both valued or both subdued.

Ne and Si

Ni and Se

Fe and Ti

Fi and Te

## Complementary functions¶

Function x in a type’s Model A always contains the same element as function x +/- 4 in its dual’s Model A. Thus the complementation of elements may be generalized to complementation of functions.

Leading and Suggestive

Creative and Mobilizing

Role and Ignoring

Vulnerable and Demonstrative

## Complementary dichotomies¶

For any given dichotomy, one’s dual has to have either the same or the opposite trait. Quadra values become a specific instance of this, due to the dichotomies of merriness and seriousness (Fe/Ti vs. Fi/Te) and judiciousness and decisiveness (Si/Ne vs. Se/Ni).