GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it

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<Verb>ContractibleSubcomplex(K):: PureCubicalComplex --> PureCubicalComplex</Verb>
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<Verb>ContractibleSubcomplex(K):: PurePermComplex --> PurePermComplex</Verb>
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<Verb>ContractibleSubcomplex(K):: SimplicialComplex --> SimplicialComplex</Verb><P/>
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<P/> Inputs a non-empty pure cubical, pure permutahedral  or simplicial complex <M>K</M> 
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and returns a contractible subcomplex.
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