Is the inclusion symbol: a contains B- then b is a subset of a or equal to a.
True inclusion: A is really included in the proper subset of B-if B = {1, 2}, then A={ 1} or {2} or an empty set.
Operation symbol:
Such as plus sign (+), minus sign (-), multiplication sign (× or), division sign (÷ or/), union of two sets (∩), intersection (∩), root sign (∩ ~), logarithm (log, lg, ln,
Relationship symbol:
For example, "=" is an equal sign, "≈" is an approximate sign, "≦" is an unequal sign and ">" is a greater than sign. "
"≒" is a similar symbol, "≒" is a complete equal sign, "∨" is a parallel symbol, "∧" is a vertical symbol, "∧" is a proportional symbol (inverse ratio can be expressed by reciprocal relationship) and "∈" is a symbol. "contained in the symbol"? "is a containing symbol," | "means" separable "(for example, a|b? It means "A is divisible by B", while ||b means that R is the greatest power of A divisible by B), and any letter such as X and Y can represent an unknown number.
Extended data:
A random phenomenon has two events a and B. If any sample point in event A must be in B, it is said that A is contained in B, or B contains A, and it is recorded as A? B or B? A, then the occurrence of event A will inevitably lead to the occurrence of event B.
The relationship between them is active and passive. A containing B means that B is a subset of A, and A containing B means that A is a subset of B. ..
For example, {1, 2,3} contains {1, 2}, but {1, 2} is contained in {1, 2,3}.
Permutation and combination symbol
c？ Number of combinations
A (or p)? number of permutations
n？ Total number of elements
r？ Number of elements participating in the selection
! ? Factorial, such as 5! =5×4×3×2× 1= 120, specify 0! = 1
! ! Half factorial (also called double factorial), for example, 7! ! =7×5×3× 1= 105, 10! ! = 10×8×6×4×2=3840
σ addition
Discrete mathematical symbol
Universal quantifier
Existential quantifier
├ determinant (formula can be proved by L)
Satisfier (formula is valid on e, and formula can be satisfied on e)
The negation of a proposition, such as the negation of a proposition is p.
∧ "He" ("And") Operation of Proposition
The "disjunctive" ("or", "combinable or") operation of propositions
→ "Conditional" Operation Proposition
"Double Condition" Operation of Proposition
p & lt= & gtq？ Equivalence relation between propositions p and q
p = & gtq？ Implication relation between proposition P and Q (P is a sufficient condition for Q, and Q is a necessary condition for P)
A* the dual formula of formula A, or the reciprocal of number theory (can also be written as
)
wff？ Combination formula
iff？ The only possibility is that
"NAND" operation of proposition ("NAND gate")
The nor operation of proposition (nor gate)
□? The modal particle "inevitable"
The modal particle "may"
null set
Belong to (such as "A∈B", that is, "A belongs to B")
Do not belong to
Power set of P(A) set a
The number of points in set a