diff --git a/src/onehot.jl b/src/onehot.jl
index 5414773c..f8061063 100644
--- a/src/onehot.jl
+++ b/src/onehot.jl
@@ -1,3 +1,5 @@
+import Base: *
+
 struct OneHotVector <: AbstractVector{Bool}
   ix::UInt32
   of::UInt32
@@ -7,7 +9,7 @@ Base.size(xs::OneHotVector) = (Int64(xs.of),)
 
 Base.getindex(xs::OneHotVector, i::Integer) = i == xs.ix
 
-Base.:*(A::AbstractMatrix, b::OneHotVector) = A[:, b.ix]
+A::AbstractMatrix * b::OneHotVector = A[:, b.ix]
 
 struct OneHotMatrix{A<:AbstractVector{OneHotVector}} <: AbstractMatrix{Bool}
   height::Int
@@ -18,7 +20,7 @@ Base.size(xs::OneHotMatrix) = (Int64(xs.height),length(xs.data))
 
 Base.getindex(xs::OneHotMatrix, i::Int, j::Int) = xs.data[j][i]
 
-Base.:*(A::AbstractMatrix, B::OneHotMatrix) = A[:, map(x->x.ix, B.data)]
+A::AbstractMatrix * B::OneHotMatrix = A[:, map(x->x.ix, B.data)]
 
 Base.hcat(x::OneHotVector, xs::OneHotVector...) = OneHotMatrix(length(x), [x, xs...])
 
@@ -47,3 +49,8 @@ argmax(y::AbstractVector, labels = 1:length(y)) =
 
 argmax(y::AbstractMatrix, l...) =
   squeeze(mapslices(y -> argmax(y, l...), y, 1), 1)
+
+# Ambiguity hack
+
+a::TrackedMatrix * b::OneHotVector = TrackedArray(Tracker.Call(*, a, b))
+a::TrackedMatrix * b::OneHotMatrix = TrackedArray(Tracker.Call(*, a, b))
diff --git a/src/tracker/Tracker.jl b/src/tracker/Tracker.jl
index 5e26a051..3a64fcb7 100644
--- a/src/tracker/Tracker.jl
+++ b/src/tracker/Tracker.jl
@@ -1,6 +1,6 @@
 module Tracker
 
-export TrackedArray, param, back!
+export TrackedArray, TrackedVector, TrackedMatrix, param, back!
 
 data(x) = x
 istracked(x) = false