Meromorphic functions #
Main statements:
MeromorphicAt
: definition of meromorphy at a pointMeromorphicAt.iff_eventuallyEq_zpow_smul_analyticAt
:f
is meromorphic atz₀
iff we havef z = (z - z₀) ^ n • g z
on a punctured neighborhood ofz₀
, for somen : ℤ
andg
analytic atz₀
.
Meromorphy of f
at x
(more precisely, on a punctured neighbourhood of x
; the value at
x
itself is irrelevant).
Equations
- MeromorphicAt f x = ∃ (n : ℕ), AnalyticAt 𝕜 (fun (z : 𝕜) => (z - x) ^ n • f z) x
Instances For
Alias of MeromorphicAt.fun_add
.
Alias of MeromorphicAt.fun_smul
.
Alias of MeromorphicAt.fun_mul
.
Finite products of meromorphic functions are analytic.
Finite products of meromorphic functions are analytic.
Alias of MeromorphicAt.fun_neg
.
Alias of MeromorphicAt.fun_sub
.
With our definitions, MeromorphicAt f x
depends only on the values of f
on a punctured
neighbourhood of x
(not on f x
)
If two functions agree on a punctured neighborhood, then one is meromorphic iff the other is so.
Alias of MeromorphicAt.fun_inv
.
Alias of MeromorphicAt.fun_div
.
Alias of MeromorphicAt.fun_pow
.
Alias of MeromorphicAt.fun_zpow
.
If a function is meromorphic at a point, then it is continuous at nearby points.
In a complete space, a function which is meromorphic at a point is analytic at all nearby
points. The completeness assumption can be dispensed with if one assumes that f
is meromorphic
on a set around x
, see MeromorphicOn.eventually_analyticAt
.
Meromorphy of a function on a set.
Equations
- MeromorphicOn f U = ∀ x ∈ U, MeromorphicAt f x
Instances For
If f
is meromorphic on U
, if g
agrees with f
on a codiscrete subset of U
and outside of
U
, then g
is also meromorphic on U
.
If f
is meromorphic on an open set U
, if g
agrees with f
on a codiscrete subset of U
, then
g
is also meromorphic on U
.
Finite products of meromorphic functions are analytic.
Finite products of meromorphic functions are analytic.