title: Default Run Command in Alloy5: what's the equivalent in Alloy4?
body: <p>I'm working on a project exam and having trouble to understand what is the equivalent of the default Run command in Alloy5 when I switch to Alloy4.</p>
  
  <p>As you all can see, if I write a model in Alloy5, but not a command (no check no run), if I click 'Execute', it executes the following command:
  "Run Default for 4 but 4 int, 4 seq expect 1"
  Which satisfies the mission of my project: check if a described model has instances. No need to check properties or something else. Just if there are instances.</p>
  
  <p>In Alloy4, if I click 'Execute', it tells me "No commands defined", so there is not a predefined run command.</p>
  
  <p>My question is: what is the equivalent of that Allloy5-Default-Run-Command in Alloy4?</p>
  
  <p>I'm going crazy since I have to work on Alloy4 API (on Java) and can't figure out how to solve this problem (because isSolvable() doesn't work if I don't put a command in the model).</p>