Proof ios stake or proof of work

I have extracted a section of the tutorial as below:

“In a Proof of Stake system, this risk can be mitigated.
Suppose malicious miner Alice wants to mine on the red chain. Even if she dedicates all of her hash power to it, she won’t get any other miner to join her on the new chain. Everyone else will still continue to mine on the blue chain because it is more profitable and risk-free to mine on the longer chain” 
Is above proof of stake of Proof of Work system?