English
From hf and hg, deduce HasFPowerSeriesWithinOnBall for f−g with pf−pg.
Русский
Из hf и hg следует HasFPowerSeriesWithinOnBall для f−g с pf−pg.
LaTeX
$$$HasFPowerSeriesWithinOnBall(f pf s x r) \\land HasFPowerSeriesWithinOnBall(g pg s x r) \\Rightarrow HasFPowerSeriesWithinOnBall(f - g, pf - pg, s, x, r)$$$
Lean4
theorem sub (hf : HasFPowerSeriesWithinOnBall f pf s x r) (hg : HasFPowerSeriesWithinOnBall g pg s x r) :
HasFPowerSeriesWithinOnBall (f - g) (pf - pg) s x r := by simpa only [sub_eq_add_neg] using hf.add hg.neg