angle as a part of the plane

Stream: general

[Yury G. Kudryashov]

What should I use in the names of lemmas about {z : ℂ | abs (arg z) ≤ θ}? I can use set_of_abs_arg_le but I would prefer something more geometric.

[Yury G. Kudryashov]

Though I'll use {z : ℂ | arg z ∈ Icc θ₁ θ₂} too so set_of_abs_arg_le/preimage_arg_Icc/... may be not too bad.

[Sebastien Gouezel]

IMHO sector sounds better. You can have the variants sector_Icc, or sector_absand so on.

[Vincent Beffara]

Or something like cone or wedge ?