English
Equivalence of absolute values is equivalent to their homeomorphism relation via WithAbs.
Русский
Эквивалентность абсолютных значений эквивалентна их гомеоморфизму через WithAbs.
LaTeX
$$$ v.IsEquiv w \leftrightarrow IsHomeomorph (WithAbs.equivWithAbs v w)$$$
Lean4
/-- Given a function `f : E → F` and a formal multilinear series `p`, we say that `f` has `p` as
a power series around `x` if `f (x + y) = ∑' pₙ yⁿ` for all `y` in a neighborhood of `0`. -/
def HasFPowerSeriesAt (f : E → F) (p : FormalMultilinearSeries 𝕜 E F) (x : E) :=
∃ r, HasFPowerSeriesOnBall f p x r