Let k be a perfect field of positive characteristic and Z an effective
Cartier divisor in the projective line over k with complement U. In this
note, we establish some results about the formal deformation theory of
overconvergent isocrystals on U with fixed "local monodromy" along Z. En
route, we show that a Hochschild cochain complex governs deformations of a
module over an arbitrary associative algebra. We also relate this Hochschild
cochain complex to a de Rham complex in order to understand the deformation
theory of a differential module over a differential ring.Comment: 59 pages; fixed typos, improved exposition; comments welcome