Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
We develop and characterize analytically an investment model in discrete time with a fixed adjustment cost not proportional to existing capital and complete irreversibility that reproduces the lumpiness of investment at the micro-level. In agreement with the empirical evidence, as a firm size increases, investment becomes less lumpy. The optimal policy is of the generalized (S,s) form.