Suppose that, in the long run,
are the proportions of buyers who buy Ambrosia, Braeburn and Cameo apples, respectively. Then the transition matrix
should leave the vector
fixed. In other words, we are looking for an eigenvector with eigenvalue 1, or an element of the null-space of the matrix
![{\displaystyle A-\mathrm {Id} =\left[{\begin{array}{ccc}-0.3&0.2&0.2\\0.2&-0.4&0.4\\0.1&0.2&-0.6\end{array}}\right].}](https://wiki.ubc.ca/api/rest_v1/media/math/render/svg/e0ff4c2bd2567334ec5c851b1d4852a65cf4cdbc)
We can find the elements of the null-space by row-reducing. Again, we indicate the row operations as in B1 (a), but we also use
for the operation "swap rows
and
".
![{\displaystyle {\begin{aligned}\left[{\begin{array}{ccc}-0.3&0.2&0.2\\0.2&-0.4&0.4\\0.1&0.2&-0.6\end{array}}\right]\xrightarrow {D_{\text{all}}(10),\ T_{1,3}} \left[{\begin{array}{ccc}1&2&-6\\2&-4&4\\-3&2&2\end{array}}\right]\xrightarrow {L_{2,1}(-2),\ L_{3,1}(3)} \left[{\begin{array}{ccc}1&2&-6\\0&-8&16\\0&8&-16\end{array}}\right]\xrightarrow {L_{3,2}(1),\ D_{2}(1/8),L_{1,2}(2)} \left[{\begin{array}{ccc}1&0&-2\\0&-1&2\\0&0&0\end{array}}\right].\end{aligned}}}](https://wiki.ubc.ca/api/rest_v1/media/math/render/svg/ce855152d696bc2bfbd87d7aae1267e1f8268b4e)
We can easily see from the row-reduced matrix above that eigenvectors of
with eigenvalue 1 are of the form
If we want the entries of this vector to be proportions of people buying the three different kinds of apples, then the entries of the eigenvector must sum up to 1. The equation
implies that
, so we have that the long-run shares of each apple variety are
![{\displaystyle v_{1}=0.4,\qquad v_{2}=0.4,\qquad v_{3}=0.2.}](https://wiki.ubc.ca/api/rest_v1/media/math/render/svg/cc35655fe3363b76c794a75dc68257d0d43b97df)