Paper 4, Section II, GAlgebraic Topology | Part II, 2009Let XXX be the subset of R4\mathbb{R}^{4}R4 given by X=A∪B∪C⊂R4X=A \cup B \cup C \subset \mathbb{R}^{4}X=A∪B∪C⊂R4, where A,BA, BA,B and CCC are defined as follows:A={(x1,x2,x3,x4)∈R4:x12+x22+x32+x42=1}B={(x1,x2,x3,x4)∈R4:x1=x2=0,x32+x42⩽1}C={(x1,x2,x3,x4)∈R4:x3=x4=0,x12+x22⩽1}\begin{aligned} &A=\left\{\left(x_{1}, x_{2}, x_{3}, x_{4}\right) \in \mathbb{R}^{4}: x_{1}^{2}+x_{2}^{2}+x_{3}^{2}+x_{4}^{2}=1\right\} \\ &B=\left\{\left(x_{1}, x_{2}, x_{3}, x_{4}\right) \in \mathbb{R}^{4}: x_{1}=x_{2}=0, x_{3}^{2}+x_{4}^{2} \leqslant 1\right\} \\ &C=\left\{\left(x_{1}, x_{2}, x_{3}, x_{4}\right) \in \mathbb{R}^{4}: x_{3}=x_{4}=0, x_{1}^{2}+x_{2}^{2} \leqslant 1\right\} \end{aligned}A={(x1,x2,x3,x4)∈R4:x12+x22+x32+x42=1}B={(x1,x2,x3,x4)∈R4:x1=x2=0,x32+x42⩽1}C={(x1,x2,x3,x4)∈R4:x3=x4=0,x12+x22⩽1}Compute H∗(X)H_{*}(X)H∗(X)Typos? Please submit corrections to this page on GitHub.