Vector is denoted as bold letter, e.g. a, Matrix is denoted as capital letter, e.g. A, ai means the ith element of a, aij means the (i,j)th element of A
All vectors are column vectors
Z is the set of integers.
Q is the set of rational numbers.
R is the set of real numbers.
C is the set of complex numbers.
F is a filtration.
P is a probability measure.
E is the expectation operator.
[n] := {1,2,⋯,n}
Zn := {0,1,⋯,n−1}
Z≥n := {i∣i∈Z∧i≥n}
R := R∪{−∞,+∞}
For X⊆R, X+ := {x∈X∣x>0}
For X⊆R, X∗ := {x∈X∣x≥0}
For a,b∈Rn,a<b := ∀i,ai≤bi
Class of sets is denoted as calligraphic letter, e.g. A, B, F
P(X) is the power set of X
⨄ represents the union of disjoint sets.
A# is the adjoint matrix of A
(X,τ) is a topological space, briefly written as X
B(X):=σ(τ), where (X,τ) is a topological space
∧ represents the and for logic, min for function
∨ represents the or for logic, max for function
2. Logic Symbols
Little letters (e.g. p,q,r) are used to represent propostional variables
¬ is used to represent negation
∧ is used to represent conjunction
∨ is used to represent disjunction
→ is used to represent implication
↔ is used to represent equivalence
A⟹B means (A→B) is True
A⟺B means ((A→B)∧(B→A)) is True
L0 is used to represent a zero-order language
L is used to represent a first-order language
mathscr upper letters (e.g. A,B,C) are used to represent the formulas (well-formed formulas,wfs) of a language L and L0
3. Computer Symbols
Local network is denoted as capital letter, e.g. A,B,C
Host in local network is denoted as small letter, e.g. a,b,c located in local network A,B,C
Public ip is denoted as Greek letter, e.g. α,γ,β
Hosts in the same local network are distinguished by subscripts, e.g. a1,a2,a5 located in local network A.