P2-irreducible manifold

From HandWiki

In mathematics, a P2-irreducible manifold is a 3-manifold that is irreducible and contains no 2-sided [math]\displaystyle{ \mathbb RP^2 }[/math] (real projective plane). An orientable manifold is P2-irreducible if and only if it is irreducible.[1] Every non-orientable P2-irreducible manifold is a Haken manifold.[2]

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