user73594: Assuming two blocks are published at exactly the same time, a race for the next block to be added to one of them begins, which eventually one chain will eventually win. 
My question: will the shorter chain still be published? Does the network still syncronize the shorter chain, i.e. does every client contain a copy of not only the longest chain, but all (for lack of a better word)  "sidechains"?
If so, are there any conditions as to what will be syncronized beyond block validity?
Thanks in advance!

user31586: 
will the shorter chain still be published?

Published -- no. However, if the stale tip was previously the best tip, it will be stored in a Bitcoin Core node implementation according to the source and other nodes can retrieve it up to a certain point in time. The time limit is imposed to avoid fingerprinting.

Does the network still synchronize the shorter chain.

No, the node only ever extends the active chain.

73594: <p>Assuming two blocks are published at exactly the same time, a race for the next block to be added to one of them begins, which eventually one chain will eventually win. </p>

<p>My question: will the shorter chain still be published? Does the network still syncronize the shorter chain, i.e. does every client contain a copy of not only the longest chain, but all (for lack of a better word)  "sidechains"?
If so, are there any conditions as to what will be syncronized beyond block validity?</p>

<p>Thanks in advance!</p>
 31586: <blockquote>
  <p>will the shorter chain still be published?</p>
</blockquote>

<p>Published -- no. However, if the stale tip was previously the best tip, it will be stored in a Bitcoin Core node implementation according to the <a href="https://github.com/bitcoin/bitcoin/blob/978682b9dccfb48425c0129431bb108e78e33e4e/src/net_processing.cpp#L953" rel="nofollow noreferrer">source</a> and other nodes can retrieve it up to a certain point in time. The time limit is imposed to avoid fingerprinting.</p>

<blockquote>
  <p>Does the network still synchronize the shorter chain.</p>
</blockquote>

<p>No, the node only ever extends the active chain.</p>
