[請益] 又是命題邏輯

看板logic作者 (Will)時間16年前 (2007/11/20 06:54), 編輯推噓2(205)
留言7則, 3人參與, 最新討論串1/2 (看更多)
想請教高手 1.) Prove A v A v A |- B -> A 下面應該是屬於論述邏輯? (Predicate Logic) 2.) |- (for all x)(A -> B -> C) -> (for all x)(A -> B) -> (for all x)(A -> C) 3.) Prove by induction on terms, that for any terms t and s, if s is a prefix of t, then the strings t and s must be identical. 我承認是問功課.... 但我真的想不出來要怎麼證明?..... 第一題只有一邊有B 是要怎麼搞 Orz..... 題外話 學期快結束了 我還真好奇我怎麼存活到現在 囧.. 感謝各位的幫忙 T_T -- The world ain't all sunshine n rainbows.It's a very mean n nasty place. N it'll beat u to ur knees n keep u there permanently if u let it. You,me or nobody's gon hit as hard as life. But it ain't about how hard u hit. It's about how hard u can get hit;how hard u can take,n keep movin forward.If u know what u'r worth, then go out n get what u'r worth. But u gotta be willing to take the hit, n not pointing fingers saying u ain't where u r becuz of him, or her or anybody. -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 76.66.133.182

11/20 07:00, , 1F
第一題,我在想是不是用soundness?
11/20 07:00, 1F

11/20 09:19, , 2F
A→(B→A)
11/20 09:19, 2F

11/20 09:20, , 3F
(AvA)→(B→A)
11/20 09:20, 3F

11/20 09:21, , 4F
(Av(AvA))→(B→A)
11/20 09:21, 4F

11/22 18:18, , 5F
第一題不能用PC規則啦 :P 那是後設的東西
11/22 18:18, 5F

11/22 18:19, , 6F
不過你這邊證明的括號很不嚴謹 :Q
11/22 18:19, 6F

11/22 18:20, , 7F
我是說題目 ^^;
11/22 18:20, 7F
文章代碼(AID): #17GXGVTn (logic)
文章代碼(AID): #17GXGVTn (logic)