# Geometría proyectiva : Center of involution

We have seen how to determine the axis of an involution and, based on the concept of polar of a point with respect to two lines, possible Involutions which can be set from four points, with their respective shafts of involution, obtaining the autopolar triangle associated which are harmonious relations of the cuadrivertice full.

In this article we will continue to enhance these elements, in particular in the autopolar triangle vertices that will determine what is known as “Center of involution”.

# Geometría proyectiva: Involution in overlapping series of second order : Axis of involution

Involutionary transformations are applications bijective of great interest to be applied in geometric constructions, since they simplify them considerably.

We will see how defined an involution in second-order series, with base a conical, Comparing the new model of transformation with overlapping series of second order previously studied.

# What is an involution in geometry?

In geometry, we speak often with terms that, in some cases, they are not sufficiently important in everyday language. This leads to create barriers in the interpretation of some simple concepts.

One of the terms that I have been asked several times in class is the of “Involution”. We define the involution.

What is an involution?