/usr/share/go-1.6/src/math/cmplx/ is in golang-1.6-src 1.6.1-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/go-1.6/src/math/cmplx/abs.go
/usr/share/go-1.6/src/math/cmplx/asin.go
/usr/share/go-1.6/src/math/cmplx/cmath_test.go
/usr/share/go-1.6/src/math/cmplx/conj.go
/usr/share/go-1.6/src/math/cmplx/exp.go
/usr/share/go-1.6/src/math/cmplx/isinf.go
/usr/share/go-1.6/src/math/cmplx/isnan.go
/usr/share/go-1.6/src/math/cmplx/log.go
/usr/share/go-1.6/src/math/cmplx/phase.go
/usr/share/go-1.6/src/math/cmplx/polar.go
/usr/share/go-1.6/src/math/cmplx/pow.go
/usr/share/go-1.6/src/math/cmplx/rect.go
/usr/share/go-1.6/src/math/cmplx/sin.go
/usr/share/go-1.6/src/math/cmplx/sqrt.go
/usr/share/go-1.6/src/math/cmplx/tan.go