Problem 1
It is the group of based-loop homotopy classes under concatenation and records one-dimensional holes.
Faculty solution guide
The Fundamental Group
Accept equivalent mathematically correct reasoning. Require explicit definitions, theorem hypotheses, proof structure, verification, and limitations.
Problem 2
Identify the first invalid inference, missing hypothesis, quantifier error, unjustified limit interchange, or unproved existence claim; then supply a valid repair.
Problem 3
A complete response explicitly states the definitions, domain, hypotheses, exact target, and theorem dependencies for The Fundamental Group.
Problem 4
The argument must address computing π₁ for basic spaces and interpreting algebraic invariants with each nontrivial step justified and the final conclusion restated.
Problem 5
A strong application explains the mathematical model in robot motion, periodic systems, knot complements, phase spaces, and obstruction theory, verifies conditions, and names at least one limitation.
Problem 6
Accept a second valid proof, a counterexample showing necessity of a hypothesis, an independent estimate, or a reproducible finite check that is correctly described as supporting evidence.