Two types of sign pervasion

1. Sign that pervades the similar class in the proof of that
   དེ་སྒྲུབ་ཀྱི་མཐུན་ཕྱོགས་ལ་ཁྱབ་བྱེད་དུ་འཇུག་པའི་རྟགས།
2. Sign that partially applies to the similar class in the proof of that
   དེ་སྒྲུབ་ཀྱི་མཐུན་ཕྱོགས་ལ་རྣམ་གཉིས་སུ་འཇུག་པའི་རྟགས།

The first is for mutually inclusive and the second for three possibilities.

Examples:
In terms of Correct effect sign:

1. Taking the subject - on the smokey mountain pass - the direct cause of smoke exists because smoke exists.
   Because if the direct cause of smoke exists, there is pervasion that smoke exists.
2. Taking the subject - on the smokey mountain pass - fire exists because smoke exists.
   Because if fire exists, there is no pervasion that smoke exists.

In terms of Correct nature sign:

1. Taking the subject - sound - it is impermanent because it is a product.
   Because if it is impermanent, it is pervaded by being a product.
2. Taking the subject - sound - it is impermanent because it is an instance of product.
   Because if it is impermanent, it is not pervaded by being an instance of product; e.g. product.

Related: Forward pervasion