In his paper [2], Paul Ehrlich write

In [1], Aubin stated a theorem which implied as a corollary that

It appears the proof in [1] is incomplete and the uniformity and correctness of Aubin's estimates even in the compact case are not clear.if a manifold $M$ admits a Riemannian metric with nonnegative Ricci curvature and all Ricci curvatures positive at some point, then $M$ admits a metric of everywhere positive Ricci curvature.

Aubin paper is a bit technical so I want to know did Paul Ehrlich have a valid point, and if so, what is it, specifically?

What specifically is the gap in Aubin's argument about positive Ricci curvature that Paul Ehrlich alludes to?

**Note 1:** As far as I understand main part of the proof of wanted theorem is in pp. 397-399.

**Note 2:** Most of people that cited Aubin's paper (about positive Ricci curvature), also cited Paul Ehrlich's paper as well. Note also that most of papers that referred to Aubin's paper is because of results about scalar curvature and Yamabe problem.

[1]: *Aubin, T.*, **Métriques riemanniennes et courbure**, J. Differ. Geom. 4, 383-424 (1970). ZBL0212.54102.

[2]: *Ehrlich, Paul*, **Metric deformations of curvature. I: Local convex deformations**, Geom. Dedicata 5, 1-23 (1976). ZBL0345.53024.

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