12、a6>=∼Z6.~~~µµµe+GkLÑ13、R>,KGzkLÑ14、R∪C0>,
15、Ù¥C0={[a,b]
16、a,b∈C}.ü+G1=17、R1>,G2=18、R2>gdȵG1∗G2=19、R1∪R2>.VanKampen½½½nnnvanKampen½½½nnnµµµX,Y´Zmf8§Z=X∪Y,A=X∩Y´ëÏ"i:A,→X,j:A,→Y´¹N"3A¥½Ä:x0,¿N´gdÈπ1(X,x0)∗π1(Y,x0)¥¹¤k/Xiπ(α)jπ(α−1)(α∈π1(A,x0))5f+§Kπ1(Z,x0)=π1(X,x0)∗π1(Y,x0)/N.`²µ(1)
20、X,YZ¹pÓφ:π1(X,x0)∗π1(Y,x0)→π1(Z,x0).(2)Z¥´þ¤a=a1···ak,zai´X½Y¥´à:3A¥"ddφ÷"(3)?X,Y9A¥´aX,aY9a÷vaX∈iπ(hai),aY∈jπ(hai),3Z¥ww,a−1Xa"Ô"ddkerφ⊇N.Y(4)kerφ⊆N,E,"ëN¹B.kkkLLLÑÑÑ+++///µµµXJ∼π1(X,x0)=21、r1,...,rp>,∼π1(Y,x0)=22、s1,...,sq>
23、,π1(A,x0)±c1,...,ck)¤,K∼π1(Z,x0)=24、r1,...,rp,s1,...,sqiπ(c1)jπ(c1)−1,...,iπ(ck)jπ(ck)−1>AAA~~~1:cãúª¥XJAüëϧK∼π1(Z,x0)=25、r1,...,rp,s1,...,sq>AAA~~~2:cãúª¥XJYüëϧK∼π1(Z,x0)=26、r1,...,rp,iπ(c1),...,iπ(ck)>½½½nn
27、nµµµòX,Y^4f8§¿?Ú¦A=X∩Y´§3Z¥mr/CÂاKvanKampen½n(ØE¤á"~~~µµµS1∨S1©)¤üÓÔduS1mf8X,Y¿§i/A=X∩Y§π111(S∨S,z0)=28、>.~~~µµµ?ÛkLÑ+29、r1,...,rp>Ñ´,ÿÀmÄ+"yyy²²²µµµÄkåX110=S
30、∨···∨{zS},P´nú:§¿π1(X0,P)=