How does the pattern of ommiting の of のは work?

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    目指すは港の赤い塔
    
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Sentence from the song "1/6 -out of the gravity".

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    残るは八人これでゲームは三分の一が終了した事になる
    
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Sentence from episode 8 of "Mirai Nikki".

Is that something grammatically wrong that people sometimes say?

