### You Can Only Cross The Same River Once

The formula is strange. For example, here’s a small proof fragment, where is an arbitrary goal formula:

Is the in the right premise of the loli-left rule the same as the one we started with in the conclusion?

The formula is strange. For example, here’s a small proof fragment, where is an arbitrary goal formula:

Is the in the right premise of the loli-left rule the same as the one we started with in the conclusion?