Chapter 1 Definitions Flashcards
Region
A connected open set
Bounded
The set G is bounded if G is a subset D[0,r] for some r.
Open Set
A Set is open if all it’s points are interior points
Closed Set
A set is closed if it contains all its boundary points.
Interior points
Suppose G is a subset of C
a € G is an interior point if some open disk with center a is a subset of G
Isolated points
G is a subset of C
A point d € G is an isolated point of G if some open disk centered at d contains no points of G other than d.
Holomorphic
The function f is holomorphic on the open set E subset G if it is differentiable at every point in E.
If a function is holomorphic on C it is said to be an entire function.
For it to be holomorphic is must be and open and nonempty set.
Open Disk
D[a,r]= { z€ C : |z-a| < r } is an open disk centered at a with radius r located inside circle C[a,r]= { z€ C : |z-a| < r }
Entire
A function that is differentiable in the whole complex plane C
Conformal
A holomorphic function with nonzero derivative preserves angles.
Continuous
Suppose f: G -> C and z_o € G
f is continuous at z_o if for very positive real number epsilon there is a positive real number delta such that
|f(z)-f(z_o)| < epsilon for all z € G
Satisfying |z-z_o| < delta
Boundary Point
Suppose G is a subset of C, b € G is a boundary point of G if every open disk centered at b contains a point in G and also a point that is not in G
Accumulation Point
Suppose G is a subset of C, c € G is an accumulation point of G if every open disk centered at c contains a point of G different from c