<p>Because $\mathbf{c}' = R'\mathbf{p}$ and $R'$ contains 3 nonzero elements in each row.</p>

CC BY-SA 3.0
2015-10-14T10:10:31.490Z
2015-10-14T10:10:31.490Z
Vladimir Lysikov
<p>There is the basic paper of S.Winograd (<a href="http://www.sciencedirect.com/science/article/pii/0024379571900097" rel="nofollow">http://www.sciencedirect.com/science/article/pii/0024379571900097</a>) about 2x2 matrix multiplication.</p>

<p>In the proof of the main Theorem 3.1, there is a some proposition that
" ... each c$^{'}_i,_j$ can be computed using only three multiplications".</p>

<p>I don't understand why.
Please help.</p>

<p>Yury</p>

<matrix-product>
Winograd's proof of the lower bound for 2x2 matrix multiplication
YurySerdyuk
# Winograd's proof of the lower bound for 2x2 matrix multiplication

(Asked by: username_0 on 2015-10-13)

There is the basic paper of S.Winograd (<http://www.sciencedirect.com/science/article/pii/0024379571900097>) about 2x2 matrix multiplication.

In the proof of the main Theorem 3.1, there is a some proposition that
" ... each c$^{'}\_i,\_j$ can be computed using only three multiplications".

I don't understand why.
Please help.

Yury

**Tags:** matrix-product


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## 1 answers

### Answer by username_1 on 2015-10-14. Score: 1

Because $\mathbf{c}' = R'\mathbf{p}$ and $R'$ contains 3 nonzero elements in each row.


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