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Revision as of 08:05, 20 May 2015
, 08:05, 20 May 2015→Getting the index of a genotype in an enumerated list given a ploidy and alleles
</math>
</math>
Because <math>a_k</math> may be 0, we will see cases of <math>\binom{k-1}{-1}</math> when <math>a_k=0</math>. This is alright because of the definition of <math>\binom{n}{r}</math>.
Because <math>a_k</math> may be 0, we will see cases of <math>\binom{k-1}{-1}</math> when <math>a_k=0</math>. This is alright because of the definition of <math>\binom{n}{r}</math> which defines this case as 0.
But to make it more sensible, we can define the function equivalently as:
But to make it more sensible, we can define the function equivalently as:
\end{align}
\end{align}
</math>
</math>
So when <math>a_k=0</math>, the binomial coefficient reads as <math>\binom{k-1}{k}</math> which is equals to since there are 0 ways to choose k items from k-1 items.
= Simple cases =
= Simple cases =
