Introduction:
The given problem involves the reaction of a mixture containing all the stereoisomers of 3, 4, 5-trimethyl cyclopentene with O3 followed by Zn-hydrolysis. We need to determine the number of different isomers of products that would result from this reaction.

Explanation:
The reaction of a mixture containing all the stereoisomers of a compound with O3 followed by Zn-hydrolysis is known as ozonolysis. Ozonolysis is a powerful tool used to determine the structure of organic compounds. It involves the cleavage of carbon-carbon double bonds, resulting in the formation of carbonyl compounds and/or carboxylic acids.

Ozonolysis of 3, 4, 5-trimethyl cyclopentene:
When 3, 4, 5-trimethyl cyclopentene undergoes ozonolysis, the carbon-carbon double bond is cleaved, resulting in the formation of two carbonyl compounds. The two carbonyl compounds can be formed in different ways, leading to different isomers of products.

Identification of different isomers:
In order to determine the number of different isomers of products, we need to consider the different ways in which the two carbonyl compounds can be formed. Let's analyze the possible scenarios:

1. Both carbonyl compounds are formed from the same carbon-carbon double bond:
In this scenario, the cleavage occurs at the same carbon-carbon double bond, resulting in two carbonyl compounds. However, since the starting compound is a mixture of stereoisomers, the two carbonyl compounds formed will be the same. Therefore, this scenario does not contribute to the number of different isomers.

2. Each carbonyl compound is formed from a different carbon-carbon double bond:
In this scenario, the cleavage occurs at different carbon-carbon double bonds, resulting in two different carbonyl compounds. Since the starting compound is a mixture of stereoisomers, this scenario can lead to different isomers of products.

Conclusion:
Based on the analysis above, we can conclude that there are four different isomers of products that would result from the ozonolysis of a mixture containing all the stereoisomers of 3, 4, 5-trimethyl cyclopentene.