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The property of being Landweber exact is independent of the orientation. In terms of Landweber's criterion, this is generally phrased as saying that the element vn is invariant modulo the ideal (p,v1,...,vn-1), and so any change-of-orientation (which induces a strict isomorphism on the formal group law) does not change the property of vn being or not being a zero divisor after modding out the previous terms.

This follows from Lemma A2.2.6 in Ravenel's green book, which implies that any endomorphism of the formal group law over an Fp-algebra R is of the form g(xph) for some h and some power series g. In particular, the p-series [p]F(x) over R/(p,v1,...,vn-1) has this property, and so the leading coefficient vn is invariant under strict isomorphisms.

It should be noted that vn is not invariant before taking this quotient, but that has no effect on whether these elements form a regular sequence in R.

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The property of being Landweber exact is independent of the orientation. In terms of Landweber's criterion, this is generally phrased as saying that the element vn is invariant modulo the ideal (p,v1,...,vn-1), and so any change-of-orientation (which induces a strict isomorphism on the formal group law) does not change the property of vn being or not being a zero divisor after modding out the previous terms.

This follows from Lemma A2.2.6 in Ravenel's green book, which implies that any endomorphism of the formal group law over an Fp-algebra R is of the form g(xph) for some h and some power series g. In particular, the p-series [p]F(x) over R/(p,v1,...,vn-1) has this property, and so the leading coefficient vn is invariant under strict isomorphisms.

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The property of being Landweber exact is independent of the orientation. In terms of Landweber's criterion, this is generally phrased as saying that the element vn is invariant modulo the ideal (p,v1,...,vn-1), and so any change-of-orientation (which induces a strict isomorphism on the formal group law) does not change the property of vn being or not being a zero divisor after modding out the previous terms.