EXAMPLE1 命题逻辑 All the following statements are propositions. Washington, D.C. is the capital of the United states of America 2. Toronto is the capital of canada 3.1+1=2 4.2+2=3 Propositions I and 3 are true, whereas 2 and 4 are false 2/24/202111:14PM Deren Chen, ZheJiang Univ
L o g i c 命题逻辑 2/24/2021 11:14 PM Deren Chen, ZheJiang Univ. 6 EXAMPLE1 All the following statements are propositions. 1. Washington, D.C., is the capital of the United States of America. 2. Toronto is the capital of Canada. 3. 1+1=2. 4. 2+2=3. Propositions 1 and 3 are true, whereas 2 and 4 are false
EXAMPLE2 命题逻辑 Consider the following sentences. What time is it? 2. Read this carefully 3.X+1=2 4. x+y=Z Sentences I and 2 are not propositions because they are not statements. Sentences 3 and 4 are not propositions because they are neither true nor false, since the variables in these sentences have not been assigned values. various ways to form propositions from sentences of this type will be discussed in Section 1.3 2/24/202111:14PM Deren Chen, ZheJiang Univ
L o g i c 命题逻辑 2/24/2021 11:14 PM Deren Chen, ZheJiang Univ. 7 EXAMPLE 2 Consider the following sentences. 1. What time is it? 2. Read this carefully. 3. x+1 =2. 4. x+y = z. Sentences 1 and 2 are not propositions because they are not statements. Sentences 3 and 4 are not propositions because they are neither true nor false, since the variables in these sentences have not been assigned values. Various ways to form propositions from sentences of this type will be discussed in Section 1.3
Log 命题逻辑 命题的语句形式 陈述句 非命题语句: 疑问句 命令句 感态句 非命题陈述句:悖论语句 2/24/202111:14PM Deren Chen, ZheJiang Univ
L o g i c 命题逻辑 2/24/2021 11:14 PM Deren Chen, ZheJiang Univ. 8 命题的语句形式 陈述句 非命题语句： 疑问句 命令句 感态句 非命题陈述句：悖论语句
Log 命题逻辑 命题的符号表示: 大小写英文字母:P、Q、R、 P、q 命题真值( TRuth values)的表示: 真:T、1 假:F 2/24/202111:14PM Deren Chen, ZheJiang Univ
L o g i c 命题逻辑 2/24/2021 11:14 PM Deren Chen, ZheJiang Univ. 9 命题的符号表示： 大小写英文字母：P、Q、R、 p 、q 、r、 命题真值（Truth Values）的表示： 真：T、1 假：F、0
Log 命题逻辑 命题语句真值确定的几点说明: 时间性 2、区域性 3、标准性 命题真值间的关系表示: 真值表( Truth Table) 2/24/202111:14PM Deren Chen, ZheJiang Univ
L o g i c 命题逻辑 2/24/2021 11:14 PM Deren Chen, ZheJiang Univ. 10 命题语句真值确定的几点说明： 1、时间性 2、区域性 3、标准性 命题真值间的关系表示： 真值表（Truth Table)