# ArgMax : Variable Domain Error

I’m attempting to utilize the ArgMax function, but am receiving the error "ArgMax::vdom: Variable domain … should be either Reals or Integers."

`ArgMax[{objective, cons == 1}, assign, {assign} ∈ {0, 1}] `

As a quick overview, we have edges denoted $$e_{i,j}$$ in $$\mathbb{R}^3$$, and we want to assign an integer value of 0 or 1 to each such that their sum is at most 1 for each set of edges. So, objective is defined as a set of sets as summations with constant coefficients $$objective = \{\{3e_{\{4, 2, -2\}, \{1, 3, 1\}\}} + 2e_{\{4, 2, -2\}, \{2, 1, 1\}\}}\}, \{7e_{\{5, 3, -1\}, \{-2, 6, -1\}\}} + 6e_{\{5, 3, -1\}, \{-1, 4, -2\}\}}\}\}$$

We also have a set of sets for constraints defined as $$cons = \{\{e_{\{\{4, 2, -2\}, \{1, 3, 1\}\}} + e_{\{\{4, 2, -2\}, \{2, 1, 1\}\}}\}, \{e_{\{\{5, 3, -1\}, \{-2, 6, -1\}\}} + e_{\{\{5, 3, -1\}, \{-1, 4, -2\}\}}\}\}$$.

Lastly, we have the variables defined in $$assign = \{e_{\{\{4, 2, -2\}, \{1, 3, 1\}\}}, e_{\{\{4, 2, -2\}, \{2, 1, 1\}\}}, e_{\{\{5, 3, -1\}, \{-2, 6, -1\}\}}, e_{\{5, 3, -1\}, \{-1, 4, -2\}\}}\}$$.

I’m new to Mathematica, so this may be a trivial fix, but if anyone can point out my error, I would greatly appreciate it.