→, the front key is true, and the back key is false. & lt—& gt； , the same is true, different is false;
Principal disjunctive normal form: the sum of the minimum terms (m); Principal conjunctive normal form: the product of the maximum term (m);
When finding the minimum term, the affirmation of the proposition argument is 1, the negation is 0, and the opposite is true when finding the maximum term;
When seeking minimax terms, each argument or argument's negation can only appear once; When seeking the minimax term, the argument is not true and disjunctive;
When seeking the normal form, in order to ensure good coding, propositional arguments should be written in the order of P, Q, R Q and R;
The term with the value of 1 in the truth table is a minimum term, and the term with the value of 0 is a maximum term;
N variables * * * have a minimum term or a maximum term, which means that (0~- 1) is just principal disjunction plus principal conjunction after simplification;
There is no main conjunctive normal form for eternal truth and no main disjunctive paradigm for eternal fallacy.
The method of deducing implication (= >): truth table method; Analysis method (assuming that the front key is true and the back key is true, assuming that the front key is false and the back key is false)
10. Reasoning and calculus methods of propositional logic: P rule, T rule ① truth table method; ② Direct proof method; 3 reduction to absurdity; ④ Additional premise method; predicate logic
Unary predicate: the predicate has only one individual, and the unary predicate describes the nature of the proposition; Multiple predicates: there are n individuals in a predicate, and multiple predicates describe the relationship between individuals;
The full-name quantifier uses implication →, and the existential quantifier uses conjunctions;
When there are both existential quantifiers and universal quantifiers, we should first eliminate existential quantifiers and then eliminate universal quantifiers; gather
N stands for natural number set, 1, 2, 3 ..., excluding 0;
Base: the number of different elements in set A, | a |
Power set: given set A, a set consisting of all subsets of set A as elements, P (a);
If set A has n elements and power set P(A) has n elements, | p (a) | = =;
Division of sets: (equivalence relation) ① Each division is a set composed of several subsets of set A; (2) The intersection of these subsets is empty, and the combination is (a);
Comparison of set division and coverage: division: each element should only appear once in a subset; Overlay: only each element is required to appear, not only once; relationship
If set A has m elements and set B has n elements, then the cardinal number of Cartesian A×B is mn, and different relationships are defined from A to B;
If the set A has n elements, then |A×A|=, a has different relations;